Question 1

Student's t is used when

Accepted Answer

A)  the sample is more than 30 observations. 
B)  the sample size is ≤ 5% of the population. 
C)  the population standard deviation is unknown. 
D)  any time. 
A)  the sample is more than 30 observations. 
B)  the sample size is ≤ 5% of the population. 
C)  the population standard deviation is unknown. 
D)  any time.

Question 2

A survey of 144 retail stores revealed that the average price of a DVD was $375 with a standard
Error of $20. If 90% and 95% conﬁdence intervals were developed to estimate the true cost of the
DVD, what similarities would they have?

Accepted Answer

A)  Point estimates 
B)  Z-values would be the same 
C)  Standard errors 
D)  Both point estimates and standard errors would be the same 
E)  Both standard errors Z-values would be the same 
A)  Point estimates 
B)  Z-values would be the same 
C)  Standard errors 
D)  Both point estimates and standard errors would be the same 
E)  Both standard errors Z-values would be the same

Question 3

The following summarizes the amount of snowfall in Ontario over the past number of years.   Determine a 95% conﬁdence interval for the average annual snowfall.

Accepted Answer

A)  [1,698, 2,046] 
B)  [1,665, 2,079] 
C)  [1,213, 2,531] 
D)  [1,783, 1,961] 
E)  [1694, 2050] 
A)  [1,698, 2,046] 
B)  [1,665, 2,079] 
C)  [1,213, 2,531] 
D)  [1,783, 1,961] 
E)  [1694, 2050]

Question 4

College X is concerned about their employees making use of their email for non-business purposes.
A random sample of 400 e-mails discovered 60 messages that were not business related. The 90%
Conﬁdence interval for the population proportion is:

Accepted Answer

A)  0.104 to 0.196 
B)  0.115 to 0.185 
C)  0.148 to 0.252 
D)  0.121 to 0.179 
E)  0.186 to 0.254 
A)  0.104 to 0.196 
B)  0.115 to 0.185 
C)  0.148 to 0.252 
D)  0.121 to 0.179 
E)  0.186 to 0.254

Question 5

College X is concerned about their employees making use of their email for non-business purposes.
A random sample of 400 e-mails discovered 70 messages that were not business related. The 95%
Conﬁdence interval for the population proportion is:

Accepted Answer

A)  0.1378 to 0.2122 
B)  0.101 to 0.199 
C)  0.1206 to.1902 
D)  0.0753 to 0.1247 
E)  0.1300 to 0.2100 
A)  0.1378 to 0.2122 
B)  0.101 to 0.199 
C)  0.1206 to.1902 
D)  0.0753 to 0.1247 
E)  0.1300 to 0.2100

Question 6

A group of statistics students decided to conduct a survey at their university to ﬁnd the average
(mean) amount of time students spent studying per week. Assuming a standard deviation of 6
Hours, what is the required sample size if the error is to be less than ½ hour with a 95% level of
Conﬁdence?

Accepted Answer

A)  554 
B)  130 
C)  35 
D)  393 
A)  554 
B)  130 
C)  35 
D)  393

Question 7

A student wanted to quickly construct a 95% conﬁdence interval for the average age of students in
Her statistics class. She randomly selected 9 students. Their average age was 19.1 years with a
Standard deviation of 1.5 years. What is the best point estimate for the population mean?

Accepted Answer

A)  2.1 years 
B)  1.5 years 
C)  19.1 years 
D)  9 years 
E)  17.6 years 
A)  2.1 years 
B)  1.5 years 
C)  19.1 years 
D)  9 years 
E)  17.6 years

Question 8

(i. Reasoning from a sample or small group to the entire group or population is called statistical
Inference.
(ii. A 95 percent conﬁdence interval implies that about 95 out of 100 similarly constructed intervals
Will include the parameter being estimated.
(iii) For a sampling distribution of the means, 95% percent of the means would be between ± 1.96
Standard deviations.

Accepted Answer

A)  (i), (ii), and (iii) are all correct statements. 
B)  (i) and (ii) are correct statements but not (iii). 
C)  (i) and (iii) are correct statements but not (ii). 
D)  (ii) and (iii) are correct statements but not (i). 
E)  (i), (ii), and (iii) are all false statements. 
A)  (i), (ii), and (iii) are all correct statements. 
B)  (i) and (ii) are correct statements but not (iii). 
C)  (i) and (iii) are correct statements but not (ii). 
D)  (ii) and (iii) are correct statements but not (i). 
E)  (i), (ii), and (iii) are all false statements.

Question 9

A conﬁdence interval for a population mean

Accepted Answer

A)  estimates the population range. 
B)  estimates a likely interval for a population mean. 
C)  estimates a likelihood or probability. 
D)  estimates the population standard deviation. 
A)  estimates the population range. 
B)  estimates a likely interval for a population mean. 
C)  estimates a likelihood or probability. 
D)  estimates the population standard deviation.

Question 10

When using Student's t to compute an interval estimate,

Accepted Answer

A)  we assume that the samples are collected from normally distributed populations. 
B)  we estimate the population standard deviation based on the sample standard deviation. 
C)  use the z distribution. 
D)  we assume that samples are collected from normally distributed populations and the estimate of the population standard deviation based on the sample standard deviation. 
E)  we assume that the samples are collected from normally distributed populations and use the z distribution. 
A)  we assume that the samples are collected from normally distributed populations. 
B)  we estimate the population standard deviation based on the sample standard deviation. 
C)  use the z distribution. 
D)  we assume that samples are collected from normally distributed populations and the estimate of the population standard deviation based on the sample standard deviation. 
E)  we assume that the samples are collected from normally distributed populations and use the z distribution.

Question 11

The Kennel Club wants to estimate the proportion of children that have a dog as a pet. Assume a
95% level of conﬁdence and that the club estimates that 30% of the children have a dog as a pet. If
The club wants the estimate to be within 3% of the population proportion, how many children would
They need to contact?

Accepted Answer

A)  978 
B)  879 
C)  789 
D)  987 
E)  897 
A)  978 
B)  879 
C)  789 
D)  987 
E)  897

Question 12

i. The test statistic t has n-1 degrees of freedom.
ii. All t distributions have the same mean of zero and a standard deviation of 1.
iii. The t distribution is more spread out and ﬂatter at the center than is the standard normal
Distribution. However, as the sample size increases, the t distribution curve approaches the
Standard normal distribution.

Accepted Answer

A)  (i), (ii), and (iii) are all correct statements. 
B)  (iii) is a correct statement but not (i) or (ii). 
C)  (i) and (iii) are correct statements but not (ii). 
D)  (ii) and (iii) are correct statements but not (i). 
E)  (i), (ii), and (iii) are all false statements. 
A)  (i), (ii), and (iii) are all correct statements. 
B)  (iii) is a correct statement but not (i) or (ii). 
C)  (i) and (iii) are correct statements but not (ii). 
D)  (ii) and (iii) are correct statements but not (i). 
E)  (i), (ii), and (iii) are all false statements.

Question 13

The manager of the college cafeteria wants to estimate the mean amount spent per customer per
Purchase. A sample of 10 customers revealed the following amounts spent:  
Find the 99 percent conﬁdence limits for the mean amount spent.
Sample mean = $4.53, s = $1.00

Accepted Answer

A)  3.53 and 5.53 
B)  3.50 and 5.56 
C)  3.48 and 5.58 
D)  3.84 and 5.85 
E)  3.35 and 5.35 
A)  3.53 and 5.53 
B)  3.50 and 5.56 
C)  3.48 and 5.58 
D)  3.84 and 5.85 
E)  3.35 and 5.35

Question 14

The following summarizes the amount of snowfall in Ontario over the past number of years.   Determine a 98% conﬁdence interval for the average annual snowfall.

Accepted Answer

A)  [1698, 2046] 
B)  [1665, 2079] 
C)  [1213, 2531] 
D)  [1783, 1961] 
E)  [1659, 2085] 
A)  [1698, 2046] 
B)  [1665, 2079] 
C)  [1213, 2531] 
D)  [1783, 1961] 
E)  [1659, 2085]

Question 15

The mean weight of trucks traveling on a particular section of Highway 401 is not known. A
Provincial highway inspector needs an estimate of the mean. He selects a random sample of 49
Trucks passing the weighing station and ﬁnds the mean is 15.8 tons, with a standard deviation of the
Sample of 3.8 tons. What is the 95 percent interval for the population mean?

Accepted Answer

A)  14.7 and 16.9 
B)  13.2 and 17.6 
C)  10.0 and 20.0 
D)  16.1 and 18.1 
A)  14.7 and 16.9 
B)  13.2 and 17.6 
C)  10.0 and 20.0 
D)  16.1 and 18.1

Question 16

Recently, a university surveyed recent graduates of the English Department for their starting
Salaries. Four hundred graduates returned the survey. The average salary was $55,000 with a
Standard deviation of $2,500.
What is the best point estimate of the population mean?

Accepted Answer

A)  $55,000 
B)  $52,500 
C)  400 
D)  $62.5 
A)  $55,000 
B)  $52,500 
C)  400 
D)  $62.5

Question 17

A statistics professor wishes to estimate the average mark on a term test for a course that has
Multiple sections and many students. A survey of some of the students registered for the course
Reveals the following results:  
The student from the course wonders whether the population mean could have been 75 or 80.

Accepted Answer

A)  Since 80 is within the 95% conﬁdence interval, the population mean is likely to be 80. 
B)  Since 80 is not within the 95% conﬁdence interval, the population mean is not likely to be 80. 
C)  Since 75 is within the 95% conﬁdence interval, the population mean is likely to be 75. 
D)  Since neither 75 nor 80 is within the 95% conﬁdence interval, the population mean is not likely to be 75 or 80. 
E)  Since 80 is not within the 95% conﬁdence interval, the population mean is not likely to be 80, but it is likely to be 75. 
A)  Since 80 is within the 95% conﬁdence interval, the population mean is likely to be 80. 
B)  Since 80 is not within the 95% conﬁdence interval, the population mean is not likely to be 80. 
C)  Since 75 is within the 95% conﬁdence interval, the population mean is likely to be 75. 
D)  Since neither 75 nor 80 is within the 95% conﬁdence interval, the population mean is not likely to be 75 or 80. 
E)  Since 80 is not within the 95% conﬁdence interval, the population mean is not likely to be 80, but it is likely to be 75.

Question 18

College X is concerned about their employees making use of their email for non-business purposes.
You have been approached to assist in this matter. College X decides on a 99% conﬁdence level
And state that the estimation proportion must be within 2 percent of the population proportion. A
Pilot survey reveals that 8 out of 50 emails sampled were not for business purposes. How many
Emails should be surveyed to meet your requirements?

Accepted Answer

A)  910 
B)  2,100 
C)  498 
D)  1,221 
E)  2,237 
A)  910 
B)  2,100 
C)  498 
D)  1,221 
E)  2,237

Question 19

If 2,000 card-carrying members of a political party were randomly sampled, and 1,600 said they
Wanted a change in leadership, what is the 95% conﬁdence interval for the true population
Percentage for all of the card-carrying members of the party who wanted a change in leadership?

Accepted Answer

A)  78.2% to 81.8% 
B)  78.0% to 82.0% 
C)  76.5% to 83.5% 
D)  77.7% to 82.3% 
E)  less than 50% 
A)  78.2% to 81.8% 
B)  78.0% to 82.0% 
C)  76.5% to 83.5% 
D)  77.7% to 82.3% 
E)  less than 50%

Question 20

A statistics professor wishes to estimate the average mark on a term test for a course that has
Multiple sections and many students. A survey of some of the students registered for the course
Reveals the following results:  
Determine a 98% conﬁdence interval for the term test results.

Accepted Answer

A)  [48.0, 93.6] 
B)  [66.8, 74.8] 
C)  [62.9, 78.71] 
D)  [64.2, 77.3] 
E)  [60.9, 80.7] 
A)  [48.0, 93.6] 
B)  [66.8, 74.8] 
C)  [62.9, 78.71] 
D)  [64.2, 77.3] 
E)  [60.9, 80.7]

Student's t is used when

A survey of 144 retail stores revealed that the average price of a DVD was $375 with a standard Error of $20. If 90% and 95% conﬁdence intervals were developed to estimate the true cost of the DVD, what similarities would they have?

The following summarizes the amount of snowfall in Ontario over the past number of years. Determine a 95% conﬁdence interval for the average annual snowfall.

College X is concerned about their employees making use of their email for non-business purposes. A random sample of 400 e-mails discovered 60 messages that were not business related. The 90% Conﬁdence interval for the population proportion is:

College X is concerned about their employees making use of their email for non-business purposes. A random sample of 400 e-mails discovered 70 messages that were not business related. The 95% Conﬁdence interval for the population proportion is:

A student wanted to quickly construct a 95% conﬁdence interval for the average age of students in Her statistics class. She randomly selected 9 students. Their average age was 19.1 years with a Standard deviation of 1.5 years. What is the best point estimate for the population mean?

A conﬁdence interval for a population mean

When using Student's t to compute an interval estimate,

The manager of the college cafeteria wants to estimate the mean amount spent per customer per Purchase. A sample of 10 customers revealed the following amounts spent: Find the 99 percent conﬁdence limits for the mean amount spent. Sample mean = $4.53, s = $1.00

The following summarizes the amount of snowfall in Ontario over the past number of years. Determine a 98% conﬁdence interval for the average annual snowfall.

Recently, a university surveyed recent graduates of the English Department for their starting Salaries. Four hundred graduates returned the survey. The average salary was $55,000 with a Standard deviation of $2,500. What is the best point estimate of the population mean?

If 2,000 card-carrying members of a political party were randomly sampled, and 1,600 said they Wanted a change in leadership, what is the 95% conﬁdence interval for the true population Percentage for all of the card-carrying members of the party who wanted a change in leadership?

A statistics professor wishes to estimate the average mark on a term test for a course that has Multiple sections and many students. A survey of some of the students registered for the course Reveals the following results: Determine a 98% conﬁdence interval for the term test results.

What Is Statistics

Describing Data: Frequencydistributions and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Pata

A Sulvey of Probability Concepts

Discrete Probability Distributions

Continuous Probabilitydistributions

Estimation and Confidence Intervals

One-Sample Tests of Hypothesis

Two Sample Tests of Hypothesis

Analysis of Variance

Linear Regression and Correlation

Multiple Regression and Correlation Analysis

Chi-Square Applications

Decision Making and Payoff Tables in Investment Scenarios

Filters

Exam 8: Sampling Methods and the Central Umit Theorem

Student's t is used when

A survey of 144 retail stores revealed that the average price of a DVD was $375 with a standard Error of $20. If 90% and 95% conﬁdence intervals were developed to estimate the true cost of the DVD, what similarities would they have?

The following summarizes the amount of snowfall in Ontario over the past number of years. Determine a 95% conﬁdence interval for the average annual snowfall.

College X is concerned about their employees making use of their email for non-business purposes. A random sample of 400 e-mails discovered 60 messages that were not business related. The 90% Conﬁdence interval for the population proportion is:

College X is concerned about their employees making use of their email for non-business purposes. A random sample of 400 e-mails discovered 70 messages that were not business related. The 95% Conﬁdence interval for the population proportion is:

A student wanted to quickly construct a 95% conﬁdence interval for the average age of students in Her statistics class. She randomly selected 9 students. Their average age was 19.1 years with a Standard deviation of 1.5 years. What is the best point estimate for the population mean?

A conﬁdence interval for a population mean

When using Student's t to compute an interval estimate,

The manager of the college cafeteria wants to estimate the mean amount spent per customer per Purchase. A sample of 10 customers revealed the following amounts spent: Find the 99 percent conﬁdence limits for the mean amount spent. Sample mean = $4.53, s = $1.00

The following summarizes the amount of snowfall in Ontario over the past number of years. Determine a 98% conﬁdence interval for the average annual snowfall.

Recently, a university surveyed recent graduates of the English Department for their starting Salaries. Four hundred graduates returned the survey. The average salary was $55,000 with a Standard deviation of $2,500. What is the best point estimate of the population mean?

If 2,000 card-carrying members of a political party were randomly sampled, and 1,600 said they Wanted a change in leadership, what is the 95% conﬁdence interval for the true population Percentage for all of the card-carrying members of the party who wanted a change in leadership?

A statistics professor wishes to estimate the average mark on a term test for a course that has Multiple sections and many students. A survey of some of the students registered for the course Reveals the following results: Determine a 98% conﬁdence interval for the term test results.

What Is Statistics

Describing Data: Frequencydistributions and Graphic Presentation

Describing Data: Numerical Measures

Describing Data: Displaying and Exploring Pata

A Sulvey of Probability Concepts

Discrete Probability Distributions

Continuous Probabilitydistributions

Estimation and Confidence Intervals

One-Sample Tests of Hypothesis

Two Sample Tests of Hypothesis

Analysis of Variance

Linear Regression and Correlation

Multiple Regression and Correlation Analysis

Chi-Square Applications

Decision Making and Payoff Tables in Investment Scenarios

Filters