Deck 8: Hypothesis Testing

Question 1

A mail-order business prides itself in its ability to fill customers' orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 30 orders was selected, the average number of days was 6.65 with a sample standard deviation of 1.5 days. Assume the time in which an order is filled is normally distributed.


-What is the critical value to test the hypotheses at ? = .10.

A)-1.282
B)-1.96
C)-1.311
D)1.282
E)1.311

Answer 1

-1.311

Question 2

Suppose we are comparing two population means from normally distributed populations based on independent random samples and unknown,but equal,population variances.If n₁ = 13 and n₂ = 10,then degrees of freedom for the t statistic is 22.

Answer 2

False

Question 3

In the past, the average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. A random sample of 16 customer transactions produces a mean waiting time of 6.3 minutes and a standard deviation of 2 minutes.

-At the 5% level of significance,how would we define the rejection region?

A)z < -1.645
B)z > 1.645
C)t > 1.753
D)t < -1.753
E)t < -1.782

Answer 3

t < -1.753

Question 4

A mail-order business prides itself in its ability to fill customers' orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 30 orders was selected, the average number of days was 6.65 with a sample standard deviation of 1.5 days. Assume the time in which an order is filled is normally distributed.


-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 5

The F distribution is skewed to the left.

Question 6

Suppose we are comparing the population variances of two normally distributed populations using independent random samples.If $s _ { 1 } ^ { 2 } = s _ { 2 } ^ { 2 }$
,the calculated value of the F statistic will always be equal to one.

Question 7

In testing the difference between population variances of two normally distributed populations using independent random samples,it is a common practice to compute the F statistic to assess if the value is greater than or equal to one.

Question 8

A mail-order business prides itself in its ability to fill customers' orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 30 orders was selected, the average number of days was 6.65 with a sample standard deviation of 1.5 days. Assume the time in which an order is filled is normally distributed.


-Calculate the appropriate test statistic to test the hypotheses.

A)2.37
B)16.90
C)0.65
D)-2.37
E)3.31

Question 9

In the past, the average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. A random sample of 16 customer transactions produces a mean waiting time of 6.3 minutes and a standard deviation of 2 minutes.


-What is the value of the appropriate test statistic?

A)t = -1.2
B)t = 2.4
C)t = -2.4
D)t = -0.6
E)t = 9.6

Question 10

Suppose we are testing a null hypothesis about the population mean of a normally distributed population.If the population standard deviation is unknown and n = 14,the appropriate test statistic is based on the ___________ distribution.

A)t
B)z
C)F
D)chi-square
E)exponential

Question 11

There are two types of machines called type A and type
B.Both type A and type B can be used to produce a certain product.The production manager wants to compare efficiency of the two machines.The manager assigns each of the 15 workers to both types of machines to compare the hourly production rate of the 15 workers.In other words,each worker operates machine A and machine B for one hour each.These two samples are independent.

Question 12

In testing the difference between population variances of two normally distributed populations using independent random samples,the F statistic can assume either a positive or a negative value.

Question 13

A paired difference experiment is an experiment in which there is relationship between the measurements in the different samples.

Question 14

In a paired difference experiment,a sample of 12 pairs of observations is collected.The degree of freedom for the t statistic is 10.

Question 15

A mail-order business prides itself in its ability to fill customers' orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 30 orders was selected, the average number of days was 6.65 with a sample standard deviation of 1.5 days. Assume the time in which an order is filled is normally distributed.


-Set up the null and alternative hypotheses to test whether the standard is being violated.

A)H₀: ? = 6 vs.H_a: ? ? 6
B)H₀: ? ? 6.65 vs.H_a: ? < 6.65
C)H₀: ? ? 6 vs.H_a: ? < 6
D)H₀: ? ? 6 vs.H_a: ? = 6
E)H₀: ? ? 6 vs.H_a: ? > 6

Question 16

The F distribution is a symmetric distribution.

Question 17

When we are comparing the population means from two normally distributed populations based on independent random samples,the pooled estimate of the variance $s _ { p } ^ { 2 }$
is used if both population standard deviations are known.

Question 18

The F distribution is skewed to the right.

Question 19

In the past, the average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. A random sample of 16 customer transactions produces a mean waiting time of 6.3 minutes and a standard deviation of 2 minutes.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 20

In testing the equality of population variances,two assumptions are required: independent samples and normally distributed populations.

Question 21

A random sample of 20 companies who announced corrections to their balance sheets took a mean time of 8.9 days for the time between balance sheet construction and the complete audit. The standard deviation of these times was 1.3 days. Assume that these times are normally distributed.


-Which of the following is the appropriate test statistic to test the hypotheses?

A)-4.82
B)36.92
C)4.71
D)-4.71
E)4.82

Question 22

When 10 randomly selected car owners are surveyed, it is found that the mean length of time they plan to keep their car is 7.01 years, and the standard deviation is 0.74 years. Assume that times are normally distributed.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 23

When 10 randomly selected car owners are surveyed, it is found that the mean length of time they plan to keep their car is 7.01 years, and the standard deviation is 0.74 years. Assume that times are normally distributed.

-The null and alternative hypotheses to test the claim that the mean for all car owners is less than 7.5 years is _____.

A)H₀: ? = 7.5 vs.H_a: ? ? 7.5
B)H₀: ? ? 7.5 vs.H_a: ? < 7.5
C)H₀: ? ? 7.01 vs.H_a: ? < 7.01
D)H₀: ? ? 7.5 vs.H_a: ? = 7.5
E)H₀: ? ? 7.5 vs.H_a: ? > 7.5

Question 24

A mail-order business prides itself in its ability to fill customers' orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 30 orders was selected, the average number of days was 6.65 with a sample standard deviation of 1.5 days. Assume the time in which an order is filled is normally distributed.


-How much evidence do we have that the standard is being met?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 25

A manufacturer of a chemical used in glue, attempting to control the amount of a hazardous chemical its workers are exposed to, has given instructions to halt production if the mean amount in the air exceeds 3.0ppm. A random sample of 50 air specimens produced the following statistics: sample mean = 3.1 ppm, sample standard deviation = 0.5 ppm. Assume measurements are normally distributed.

-The appropriate test statistic to test the hypotheses is _____.

A)1.00
B)-1.00
C)2.80
D)1.41
E)-1.41

Question 26

The manufacturer of an over-the-counter heartburn relief mediation claims that it product brings relief in less than 3.5 minutes, on average. To be able to make this claim the manufacturer was required to present statistical evidence in support of the claim. The manufacturer reported that for a sample of 50 heartburn sufferers, the mean time to relief was 3.3 minutes and the standard deviation was 1.1 minutes. Assume that time is normally distributed.

-The appropriate test statistic to test the hypotheses is _____.

A)1.286
B)9.09
C)-1.286
D)-2.58
E)-9.09

Question 27

A study investigated the relationship of employment status to mental health. A sample of 49 unemployed men took a mental health examination measuring present mental health with lower values indicating better mental health. Their mean score was 11.50 and a standard deviation of 3. Assume that scores are normally distributed.

-How much evidence do we have that the mean score exceeds 10?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 28

When 10 randomly selected car owners are surveyed, it is found that the mean length of time they plan to keep their car is 7.01 years, and the standard deviation is 0.74 years. Assume that times are normally distributed.

-How much evidence is there that the mean years is less than 7.5?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 29

A study investigated the relationship of employment status to mental health. A sample of 49 unemployed men took a mental health examination measuring present mental health with lower values indicating better mental health. Their mean score was 11.50 and a standard deviation of 3. Assume that scores are normally distributed.

-The null and alternative hypotheses if we wish to test the research hypothesis that the mean score for all unemployed men exceeds 10 is _____.

A)H₀: ? = 10 vs.H_a: ? ? 10
B)H₀: ? ? 10.94 vs.H_a: ? < 10.94
C)H₀: ? ? 10 vs.H_a: ? < 10
D)H₀: ? ?10 vs.H_a: ? = 10
E)H₀: ? ? 10 vs.H_a: ? > 10

Question 30

The manufacturer of an over-the-counter heartburn relief mediation claims that it product brings relief in less than 3.5 minutes, on average. To be able to make this claim the manufacturer was required to present statistical evidence in support of the claim. The manufacturer reported that for a sample of 50 heartburn sufferers, the mean time to relief was 3.3 minutes and the standard deviation was 1.1 minutes. Assume that time is normally distributed.

-The null and alternative hypotheses to test the manufacturer's claim is _____.

A)H₀: ? = 3.3 vs.H_a: ? ? 3.3
B)H₀: ? ? 3.5 vs.H_a: ? < 3.5
C)H₀: ? ? 3.3 vs.H_a: ? < 3.3
D)H₀: ? ? 3.5 vs.H_a: ? = 3.5
E)H₀: ? ? 3.5 vs.H_a: ? > 3.5

Question 31

A study investigated the relationship of employment status to mental health. A sample of 49 unemployed men took a mental health examination measuring present mental health with lower values indicating better mental health. Their mean score was 11.50 and a standard deviation of 3. Assume that scores are normally distributed.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.0005 < p-value < 0.001
D)0.05 < p-value < 0.10
E)p-value > 0.10

Question 32

A random sample of 20 companies who announced corrections to their balance sheets took a mean time of 8.9 days for the time between balance sheet construction and the complete audit. The standard deviation of these times was 1.3 days. Assume that these times are normally distributed.

-What is the rejection point for ? = .001 to test the hypotheses.

A)2.575
B)3.579
C)-1.96
D)-2.575
E)-3.579

Question 33

A random sample of 20 companies who announced corrections to their balance sheets took a mean time of 8.9 days for the time between balance sheet construction and the complete audit. The standard deviation of these times was 1.3 days. Assume that these times are normally distributed.


-The null and alternative hypotheses to provide evidence supporting the claim that ? is greater than 7.5 days which was the previous year amount is _____.

A)H_O: ? = 7.5 vs.H_A: ? ? 7.5
B)H_O: ? ? 7.5 vs.H_A: ? < 7.5
C)H_O: ? ? 8.9 vs.H_A: ? < 8.9
D)H_O: ? ? 7.5 vs.H_A: ? = 7.5
E)H_O: ? ? 7.5 vs.H_A: ? > 7.5

Question 34

The manufacturer of an over-the-counter heartburn relief mediation claims that it product brings relief in less than 3.5 minutes, on average. To be able to make this claim the manufacturer was required to present statistical evidence in support of the claim. The manufacturer reported that for a sample of 50 heartburn sufferers, the mean time to relief was 3.3 minutes and the standard deviation was 1.1 minutes. Assume that time is normally distributed.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)p-value > 0.10

Question 35

The manufacturer of an over-the-counter heartburn relief mediation claims that it product brings relief in less than 3.5 minutes, on average. To be able to make this claim the manufacturer was required to present statistical evidence in support of the claim. The manufacturer reported that for a sample of 50 heartburn sufferers, the mean time to relief was 3.3 minutes and the standard deviation was 1.1 minutes. Assume that time is normally distributed.

-How much evidence do we have that the claim is true?

A)Little or no evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 36

A random sample of 20 companies who announced corrections to their balance sheets took a mean time of 8.9 days for the time between balance sheet construction and the complete audit. The standard deviation of these times was 1.3 days. Assume that these times are normally distributed.

-How much evidence do we have that the time is longer than 7.5 days?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 37

When 10 randomly selected car owners are surveyed, it is found that the mean length of time they plan to keep their car is 7.01 years, and the standard deviation is 0.74 years. Assume that times are normally distributed.

-The appropriate test statistic to test the hypotheses is _____.

A)-13.10
B)-2.53
C)-2.09
D)2.09
E)2.53

Question 38

A manufacturer of a chemical used in glue, attempting to control the amount of a hazardous chemical its workers are exposed to, has given instructions to halt production if the mean amount in the air exceeds 3.0ppm. A random sample of 50 air specimens produced the following statistics: sample mean = 3.1 ppm, sample standard deviation = 0.5 ppm. Assume measurements are normally distributed.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 39

A manufacturer of a chemical used in glue, attempting to control the amount of a hazardous chemical its workers are exposed to, has given instructions to halt production if the mean amount in the air exceeds 3.0ppm. A random sample of 50 air specimens produced the following statistics: sample mean = 3.1 ppm, sample standard deviation = 0.5 ppm. Assume measurements are normally distributed.

-The null and alternative hypotheses that would be used to halt production is ______.

A)H₀: ? = 3.0 vs.H_a: ? ? 3.0
B)H₀: ? ? 3.0 vs.H_a: ? < 3.0
C)H₀: ? ? 3.1 vs.H_a: ? < 3.1
D)H₀: ? ? 3.0 vs.H_a: ? = 3.0
E)H₀: ? ? 3.0 vs.H_a: ? > 3.0

Question 40

A study investigated the relationship of employment status to mental health. A sample of 49 unemployed men took a mental health examination measuring present mental health with lower values indicating better mental health. Their mean score was 11.50 and a standard deviation of 3. Assume that scores are normally distributed.

-The appropriate test statistic to test the hypotheses is _____.

A)2.97
B)-2.97
C)2.68
D)3.50
E)-3.50

Question 41

A machine has been designed to make nails which are 8cm long with a standard deviation of 0.15cm. A sample of 48 nails is selected periodically to assess if the length is too variable from the standard of 8cm. From the sample of 48 nails, the mean is found to be 7.983cm. Assume the lengths are normally distributed.

-The null and alternative hypotheses to test the nail length is _____.

A)H₀ :µ ? 8 H_a :µ = 8
B)H₀ :µ ? 7.983 H_a :µ > 7.983
C)H₀ :µ ? 8 H_a :µ > 8
D)H₀ :µ ? 8 H_a :µ < 8
E)H₀ :µ = 8 H_a :µ ? 8

Question 42

A machine has been designed to make nails which are 8cm long with a standard deviation of 0.15cm. A sample of 48 nails is selected periodically to assess if the length is too variable from the standard of 8cm. From the sample of 48 nails, the mean is found to be 7.983cm. Assume the lengths are normally distributed.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.10 < p-value < 0.20
E)p-value > 0.20

Question 43

An injector molder produces plastic pens. The process is designed to produce pens with a mean weight of 0.250 grams. To investigate whether the injection molder is operating satisfactorily, 40 pens were randomly sample with a mean of 0.2525g and a standard deviation of .0022g.

-How would you define the rejection region for this test at ? = .001?

A)t > 2.575
B)t > 2.33
C)t > 1.96 and t < -1.96
D)t > 3.29 and t < -3.29
E)t > 3.558 and t < -3.558

Question 44

It is estimated that the average adult spends $123 in entertainment costs per month. Some believe this figure is too high and conducted a survey of 40 randomly selected adults. They found a mean of $113.03 per month was spent and a standard deviation of $25.99.

-The null and alternative hypotheses to test the claim that the entertainment expenses per month are less than the estimate is _____.

A)H₀: ? = 123 vs.H_a: ? ? 123
B)H₀: ? ? 123 vs.H_a: ? < 123
C)H₀: ? ? 113.03 vs.H_a: ? < 113.03
D)H₀: ? ? 123 vs.H_a: ? = 123
E)H₀: ? ? 123 vs.H_a: ? > 123

Question 45

It is estimated that the average adult spends $123 in entertainment costs per month. Some believe this figure is too high and conducted a survey of 40 randomly selected adults. They found a mean of $113.03 per month was spent and a standard deviation of $25.99.

-How much evidence do we have that the monthly entertainment costs are less than the estimate?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 46

Standard x-ray machines should give radiation dosages below 5.00 mill roentgens (mil-r). To test a certain x-ray machine, a sample of 36 observations is taken with a mean of 4.13 mil-r and a standard deviation of 1.91 mil-r.

-How much evidence do we have that the machine is in specification?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 47

It has been hypothesized that on average employees spend one hour a day playing video games at work. To test this claim, a manager takes a random sample of 35 employees who showed a mean time of 55 minutes per day with a standard deviation of 5 minutes.

-How would you define the rejection region for this test at ? = .01?

A)t > 2.575
B)t > 2.33
C)t > 1.96 and t < -1.96
D)t > 3.29 and t < -3.29
E)t > 2.728 and t < -2.728

Question 48

Standard x-ray machines should give radiation dosages below 5.00 mill roentgens (mil-r). To test a certain x-ray machine, a sample of 36 observations is taken with a mean of 4.13 mil-r and a standard deviation of 1.91 mil-r.

-The null and alternative hypotheses to test whether this particular machine gives radiation below 5.00 mil-r (is in specification)is _____.

A)H₀: ? = 5 vs.H_a: ? ? 5
B)H₀: ? ? 5 vs.H_a: ? < 5
C)H₀: ? ? 4.13 vs.H_a: ? < 4.13
D)H₀: ? ? 5 vs.H_a: ? = 5
E)H₀: ? ? 5 vs.H_a: ? > 5

Question 49

A machine has been designed to make nails which are 8cm long with a standard deviation of 0.15cm. A sample of 48 nails is selected periodically to assess if the length is too variable from the standard of 8cm. From the sample of 48 nails, the mean is found to be 7.983cm. Assume the lengths are normally distributed.

-How much evidence is there that the nails made are not long enough?

A)Little to no evidence
B)Some evidence
C)Strong evidence
D)Very Strong evidence
E)Extremely Strong evidence

Question 50

A machine has been designed to make nails which are 8cm long with a standard deviation of 0.15cm. A sample of 48 nails is selected periodically to assess if the length is too variable from the standard of 8cm. From the sample of 48 nails, the mean is found to be 7.983cm. Assume the lengths are normally distributed.

-The test statistic is _____.

A)-0.785
B)-1.57
C)-3.04
D)1.57
E)0.785

Question 51

An injector molder produces plastic pens. The process is designed to produce pens with a mean weight of 0.250 grams. To investigate whether the injection molder is operating satisfactorily, 40 pens were randomly sample with a mean of 0.2525g and a standard deviation of .0022g.

-The test statistic is _____.

A)7.187
B)337
C)3.371
D)-.337
E)-7.187

Question 52

It is estimated that the average adult spends $123 in entertainment costs per month. Some believe this figure is too high and conducted a survey of 40 randomly selected adults. They found a mean of $113.03 per month was spent and a standard deviation of $25.99.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 53

An injector molder produces plastic pens. The process is designed to produce pens with a mean weight of 0.250 grams. To investigate whether the injection molder is operating satisfactorily, 40 pens were randomly sample with a mean of 0.2525g and a standard deviation of .0022g.

-The appropriate hypotheses to test that the process is performing satisfactorily is _____.

A)H ₀: µ ? 0.250 H_a :µ < 0.250
B)H ₀ :µ = 0.250 H_a :µ ? 0.250
C)H ₀ :µ ? 0.250 H_a :µ > 0.250
D)H ₀: µ ? 0.250 H_a :µ = 0.250
E)H ₀ :µ ? 0.2525 H_a :µ > 0.2525

Question 54

A manufacturer of a chemical used in glue, attempting to control the amount of a hazardous chemical its workers are exposed to, has given instructions to halt production if the mean amount in the air exceeds 3.0ppm. A random sample of 50 air specimens produced the following statistics: sample mean = 3.1 ppm, sample standard deviation = 0.5 ppm. Assume measurements are normally distributed.

-How much evidence is there that the mean is greater than 3 ppm?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 55

Standard x-ray machines should give radiation dosages below 5.00 mill roentgens (mil-r). To test a certain x-ray machine, a sample of 36 observations is taken with a mean of 4.13 mil-r and a standard deviation of 1.91 mil-r.

-The appropriate test statistic to test the hypotheses is _____.

A)-2.73
B)-3.78
C)-0.455
D)3.78
E)2.73

Question 56

It has been hypothesized that on average employees spend one hour a day playing video games at work. To test this claim, a manager takes a random sample of 35 employees who showed a mean time of 55 minutes per day with a standard deviation of 5 minutes.

-The test statistic is _____.

A)5.92
B)63.89
C)11.84
D)-5.92
E)-63.89

Question 57

It has been hypothesized that on average employees spend one hour a day playing video games at work. To test this claim, a manager takes a random sample of 35 employees who showed a mean time of 55 minutes per day with a standard deviation of 5 minutes.

-The null and alternative hypothesis to test the claim that the company's playing time differs from the national average is _____.

A)H₀ :µ ? 60 H_a :µ > 60
B)H₀ :µ ? 60 H_a :µ< 60
C)H₀ :µ = 55 H_a :µ ? 55
D)H₀ :µ = 60 H_a :µ ? 60
E)H₀ :µ ? 60 H_a :µ = 60

Question 58

It is estimated that the average adult spends $123 in entertainment costs per month. Some believe this figure is too high and conducted a survey of 40 randomly selected adults. They found a mean of $113.03 per month was spent and a standard deviation of $25.99.

-The appropriate test statistic to test the hypotheses is _____.

A)-0.38
B)2.43
C)0.38
D)-15.34
E)-2.43

Question 59

Standard x-ray machines should give radiation dosages below 5.00 mill roentgens (mil-r). To test a certain x-ray machine, a sample of 36 observations is taken with a mean of 4.13 mil-r and a standard deviation of 1.91 mil-r.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 60

An injector molder produces plastic pens. The process is designed to produce pens with a mean weight of 0.250 grams. To investigate whether the injection molder is operating satisfactorily, 40 pens were randomly sample with a mean of 0.2525g and a standard deviation of .0022g.

-How much evidence do we have that the process is out of control?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very Strong evidence
E)Extremely Strong evidence

Question 61

In research on cell phone use by teenagers it was found that the average time for a call was at least 15 minutes. Social psychologists feel that this study understated the time. To determine this claim, cell phone bills for 15 teenagers were evaluated. On average, the time spent was 18.5 minutes per call with a sample standard deviation of four minutes (assume a normal distribution).

-How would you define the rejection region for this test at ? = .001?

A)t > 1.711
B)t > 2.33
C)t > 2.492
D)t > 3.646 and t < -3.646
E)t > 3.787

Question 62

The manager of a local specialty store is concerned with a possible slowdown in payments by her customers. She measures the rate of payment in terms of the average number of days receivables are outstanding. Generally, the store has maintained an average of 50 days with a standard deviation of 10 days. A random sample of 25 accounts gives an average of 54 days outstanding with a standard deviation of 8 days. Assume the number of days is approximately normally distributed.

-How much evidence do we have that there is a slowdown?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 63

The manager of a local specialty store is concerned with a possible slowdown in payments by her customers. She measures the rate of payment in terms of the average number of days receivables are outstanding. Generally, the store has maintained an average of 50 days with a standard deviation of 10 days. A random sample of 25 accounts gives an average of 54 days outstanding with a standard deviation of 8 days. Assume the number of days is approximately normally distributed.

-The appropriate test statistic to test the hypotheses is _____.

A)-2.00
B)-2.50
C)12.50
D)2.50
E)2.00

Question 64

A wine manufacturer is concerned that the percentage of alcohol in each bottle may not be the 13% as advertised on the bottle. A random sample of 31 bottles is tested. The average alcohol percentage is 12.58% and the standard deviation is 0.25%. Assume alcohol content is normally distributed.

-How would you define the rejection region for this test at ? = .001?

A)t > 2.575
B)t > 2.33
C)t > 1.96 and t < -1.96
D)t > 3.646 and t < -3.646
E)t > 2.728 and t < -2.728

Question 65

Last year, during an investigation of the time spent reading e-mails on a daily basis, researchers found that on Monday the average time was 50 minutes. Office workers claim that with the increased spam and junk mail, this time has now increased. To conduct a test, a sample of 25 employees is selected with the following results: sample mean = 51.05 minutes and sample standard deviation = 14.2 minutes. Assume times are normally distributed.

-How would you define the rejection region for this test at ? = .05?

A)t > 1.711
B)t > 2.33
C)t > 1.96 and t < -1.96
D)t > 3.646 and t < -3.646
E)t > 2.728 and t < -2.728

Question 66

A wine manufacturer is concerned that the percentage of alcohol in each bottle may not be the 13% as advertised on the bottle. A random sample of 31 bottles is tested. The average alcohol percentage is 12.58% and the standard deviation is 0.25%. Assume alcohol content is normally distributed.

-How much evidence is there that the mean of the percentage of alcohol is not 13%?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very Strong evidence
E)Extremely Strong evidence

Question 67

In research on cell phone use by teenagers it was found that the average time for a call was at least 15 minutes. Social psychologists feel that this study understated the time. To determine this claim, cell phone bills for 15 teenagers were evaluated. On average, the time spent was 18.5 minutes per call with a sample standard deviation of four minutes (assume a normal distribution).

-The null and alternative hypotheses to test whether the original research claim is valid is _____.

A)H₀: ? = 15 vs.H_a: ? ? 15
B)H₀: ? ? 15 vs.H_a: ? < 15
C)H₀: ? ? 18.5 vs.H_a: ? < 18.5
D)H₀: ? ? 15 vs.H_a: ? = 15
E)H₀: ? ? 15 vs.H_a: ? > 15

Question 68

The manager of a local specialty store is concerned with a possible slowdown in payments by her customers. She measures the rate of payment in terms of the average number of days receivables are outstanding. Generally, the store has maintained an average of 50 days with a standard deviation of 10 days. A random sample of 25 accounts gives an average of 54 days outstanding with a standard deviation of 8 days. Assume the number of days is approximately normally distributed.

-How would you define the rejection region for this test at ? = .01?

A)t > 1.711
B)t > 2.33
C)t > 2.492
D)t > 3.646 and t < -3.646
E)t > 2.728 and t < -2.728

Question 69

In research on cell phone use by teenagers it was found that the average time for a call was at least 15 minutes. Social psychologists feel that this study understated the time. To determine this claim, cell phone bills for 15 teenagers were evaluated. On average, the time spent was 18.5 minutes per call with a sample standard deviation of four minutes (assume a normal distribution).

-The appropriate test statistic to test the hypotheses is _____.

A)3.39
B)13.125
C)0.875
D)-0.875
E)-3.39

Question 70

The local pharmacy prides itself on the accuracy of the number of tablets that are dispensed in a 60 count prescription. The new manager feels that the pharmacy assistants might have become careless in counting due to an increase in the volume of prescriptions. To test this theory, the manager randomly selects 40 prescriptions requiring 60 tablets and recounts the number in each bottle. The manager finds a sample mean of 62.05 and a standard deviation of 4.45. Assume counts are approximately normally distributed.

-Give a range for the p-value for this test.

A)0.01 < p-value < 0.025
B)0.001 < p-value < 0.005
C)0.005 < p-value < 0.01
D)0.05 < p-value < 0.10
E)0.025 < p-value < 0.05

Question 71

A wine manufacturer is concerned that the percentage of alcohol in each bottle may not be the 13% as advertised on the bottle. A random sample of 31 bottles is tested. The average alcohol percentage is 12.58% and the standard deviation is 0.25%. Assume alcohol content is normally distributed.

-The null and alternative hypothesis to test if the alcohol percentage is different from 13% is _____.

A)H₀ :µ ? 13 H_a :µ < 13
B)H₀ :µ = 13 H_a :µ ? 13
C)H₀ :µ ? 13 H_a :µ > 13
D)H₀ :µ ? 13 H_a:µ = 13
E)H₀ :µ ? 12.58 H_a :µ > 12.58

Question 72

It has been hypothesized that on average employees spend one hour a day playing video games at work. To test this claim, a manager takes a random sample of 35 employees who showed a mean time of 55 minutes per day with a standard deviation of 5 minutes.

-How much evidence do we have that this company's employees are different from the average employee?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very Strong evidence
E)Extremely Strong evidence

Question 73

The local pharmacy prides itself on the accuracy of the number of tablets that are dispensed in a 60 count prescription. The new manager feels that the pharmacy assistants might have become careless in counting due to an increase in the volume of prescriptions. To test this theory, the manager randomly selects 40 prescriptions requiring 60 tablets and recounts the number in each bottle. The manager finds a sample mean of 62.05 and a standard deviation of 4.45. Assume counts are approximately normally distributed.

-How much evidence do we have to reject the null hypothesis?

A)No evidence
B)Some evidence
C)Strong evidence
D)Very Strong evidence
E)Extremely Strong evidence

Question 74

Last year, during an investigation of the time spent reading e-mails on a daily basis, researchers found that on Monday the average time was 50 minutes. Office workers claim that with the increased spam and junk mail, this time has now increased. To conduct a test, a sample of 25 employees is selected with the following results: sample mean = 51.05 minutes and sample standard deviation = 14.2 minutes. Assume times are normally distributed.

-How much evidence do we have that the workers' claim is true?

A)Little to no evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question 75

Last year, during an investigation of the time spent reading e-mails on a daily basis, researchers found that on Monday the average time was 50 minutes. Office workers claim that with the increased spam and junk mail, this time has now increased. To conduct a test, a sample of 25 employees is selected with the following results: sample mean = 51.05 minutes and sample standard deviation = 14.2 minutes. Assume times are normally distributed.

-The appropriate test statistic to test the hypotheses is _____.

A)2.38
B)0.37
C)-1.19
D)1.76
E)-1.76

Question 76

A wine manufacturer is concerned that the percentage of alcohol in each bottle may not be the 13% as advertised on the bottle. A random sample of 31 bottles is tested. The average alcohol percentage is 12.58% and the standard deviation is 0.25%. Assume alcohol content is normally distributed.

-The test statistic to test these hypotheses is _____.

A)9.35
B)-9.35
C)4.68
D)-4.68
E)-1.68

Question 77

The local pharmacy prides itself on the accuracy of the number of tablets that are dispensed in a 60 count prescription. The new manager feels that the pharmacy assistants might have become careless in counting due to an increase in the volume of prescriptions. To test this theory, the manager randomly selects 40 prescriptions requiring 60 tablets and recounts the number in each bottle. The manager finds a sample mean of 62.05 and a standard deviation of 4.45. Assume counts are approximately normally distributed.

-The null and alternative hypothesis to test if the average number of tablets is different from the required number is _____.

A)H₀ :µ ? 60 H_a :µ = 60
B)H₀ :µ ? 40 H_a :µ < 40
C)H₀ :µ ? 60 H_a :µ < 60
D)H₀ :µ ? 60 H_a: µ > 60
E)H₀ :µ = 60 H_a :µ ? 60

Question 78

The local pharmacy prides itself on the accuracy of the number of tablets that are dispensed in a 60 count prescription. The new manager feels that the pharmacy assistants might have become careless in counting due to an increase in the volume of prescriptions. To test this theory, the manager randomly selects 40 prescriptions requiring 60 tablets and recounts the number in each bottle. The manager finds a sample mean of 62.05 and a standard deviation of 4.45. Assume counts are approximately normally distributed.

-The test statistic is _____.

A)2.91
B)-2.91
C)-3.57
D)6.15
E)3.57

Question 79

The manager of a local specialty store is concerned with a possible slowdown in payments by her customers. She measures the rate of payment in terms of the average number of days receivables are outstanding. Generally, the store has maintained an average of 50 days with a standard deviation of 10 days. A random sample of 25 accounts gives an average of 54 days outstanding with a standard deviation of 8 days. Assume the number of days is approximately normally distributed.

-The null and alternative hypotheses needed to show that there has been a slowdown in payments by the company's customers is _____.

A)H₀: ? = 50 vs.H_a: ? ? 50
B)H₀: ? ? 54 vs.H_a: ? < 54
C)H₀: ? ? 50 vs.H_a: ? < 50
D)H₀: ? ? 50 vs.H_a: ? = 50
E)H₀: ? ? 50 vs.H_a: ? > 50

Question 80

Last year, during an investigation of the time spent reading e-mails on a daily basis, researchers found that on Monday the average time was 50 minutes. Office workers claim that with the increased spam and junk mail, this time has now increased. To conduct a test, a sample of 25 employees is selected with the following results: sample mean = 51.05 minutes and sample standard deviation = 14.2 minutes. Assume times are normally distributed.

-The null and alternative hypotheses to test the workers' claim is _____.

A)H₀: ? = 50 vs.H_a: ? ? 50
B)H₀: ? ? 50 vs.H_a: ? < 50
C)H₀: ? ? 51.05 vs.H_a: ? < 51.05
D)H₀: ? ? 50 vs.H_a: ? = 50
E)H₀: ? ? 50 vs.H_a: ? > 50