Question 1

A two-tailed test is conducted at the 5% significance level. Which of the z-scores below is the smallest one that leads to rejection of the null hypothesis?

Accepted Answer

A)  1.12 
B)  1.48 
C)  1.84 
D)  2.15 
A)  1.12 
B)  1.48 
C)  1.84 
D)  2.15

Question 2

A researcher claims that more than 62% of voters favor gun control. State the null hypothesis and the alternative hypothesis for a test of significance.

Accepted Answer

A) $\mathrm { H } _ { 0 } : \mathrm { p } > 0.62$ $\mathrm { H } _ { \mathrm { a } } : \mathrm { p } = 0.62$ B) $\mathrm { H } _ { 0 } : \mathrm { p } 0.62$ D) $\mathrm { H } _ { 0 } : \mathrm { p } = 0.62$ $\mathrm { H } _ { \mathrm { a } } : \mathrm { p } < 0.62$ A) $\mathrm { H } _ { 0 } : \mathrm { p } > 0.62$ $\mathrm { H } _ { \mathrm { a } } : \mathrm { p } = 0.62$ B) $\mathrm { H } _ { 0 } : \mathrm { p } 0.62$ D) $\mathrm { H } _ { 0 } : \mathrm { p } = 0.62$ $\mathrm { H } _ { \mathrm { a } } : \mathrm { p } < 0.62$

Question 3

A health insurer has determined that the "reasonable and customary" fee for a certain medical procedure is $1200. They suspect that the average fee charged by one particular clinic for this procedure is higher than $1200. The insurer wants to perform a hypothesis test to determine whether their suspicion is correct. The hypotheses are: $$
\begin{array}{l}
\mathrm{H}_{0}: \mu=\$ 1200 \
\mathrm{H}_{\mathrm{a}}: \mu>\$ 1200
\end{array}
$$
Explain the meaning of a correct decision.

Accepted Answer

A)  Concluding that $ \mu>\$ 1200 $ when in fact $ \mu=\$ 1200 $ 
B)  Concluding that $ \mu\$ 1200 $ 
D)  Failing to reject the hypothesis that $ \mu=\$ 1200 $ when in fact $ \mu=\$ 1200 $ OR concluding that $ \mu> $ $ \$ 1200 $ when in fact $ \mu>\$ 1200 $ 
A)  Concluding that $ \mu>\$ 1200 $ when in fact $ \mu=\$ 1200 $ 
B)  Concluding that $ \mu\$ 1200 $ 
D)  Failing to reject the hypothesis that $ \mu=\$ 1200 $ when in fact $ \mu=\$ 1200 $ OR concluding that $ \mu> $ $ \$ 1200 $ when in fact $ \mu>\$ 1200 $

Question 4

The manufacturer of a refrigerator system for beer kegs produces refrigerators that are supposed to maintain a true mean temperature, µ, of 45ºF, ideal for a certain type of German pilsner. The owner of the brewery does not agree with the refrigerator manufacturer, and claims that the true mean temperature is incorrect. Assume that a hypothesis test of the claim has been conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population to which the results of the test apply.

Accepted Answer

A)  All refrigerators produced by the manufacturer specifically to cool kegs of a particular German pilsner beer 
B)  All refrigerators produced by the manufacturer 
C)  All refrigerators produced by the manufacturer specifically to cool kegs of beer 
D)  There is not sufficient description to identify the population. 
A)  All refrigerators produced by the manufacturer specifically to cool kegs of a particular German pilsner beer 
B)  All refrigerators produced by the manufacturer 
C)  All refrigerators produced by the manufacturer specifically to cool kegs of beer 
D)  There is not sufficient description to identify the population.

Question 5

A consumer group claims that the mean running time for a certain type of flashlight battery is not the same as the manufacturer's claims. Determine the null and alternative hypotheses for the test
Described.

Accepted Answer

A)  $ \mathrm{H}_{0}: \mu= $ Manufacturer's claims
$ \mathrm{H}_{\mathrm{a}}: \mu $ Manufacturer's claims 
D)  $ \mathrm{H}_{0}: \mu \neq $ Manufacturer's claims 
$ \mathrm{H}_{\mathrm{a}}: \mu= $ Manufacturer's claims 
A)  $ \mathrm{H}_{0}: \mu= $ Manufacturer's claims
$ \mathrm{H}_{\mathrm{a}}: \mu $ Manufacturer's claims 
D)  $ \mathrm{H}_{0}: \mu \neq $ Manufacturer's claims 
$ \mathrm{H}_{\mathrm{a}}: \mu= $ Manufacturer's claims

Question 6

A manufacturer claims that the mean amount of juice in its 16 ounce bottles is 16.1 ounces. A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this. The hypotheses are: 
$ \mathrm{H}_{0}: \mu=16.1 $ ounces
$\mathrm{H}_{\mathrm{a}}: \mu<16.1 \text { ounces }
$
 Suppose that the results of the sampling lead to rejection of the null hypothesis. Classify that conclusion as a Type I error, a Type II error, or a correct decision, if in fact the mean amount of juice, ?, is less than 16.1 ounces.

Accepted Answer

A)  Type II error 
B)  Correct decision 
C)  Type I error 
A)  Type II error 
B)  Correct decision 
C)  Type I error

Question 7

A two-tailed test is conducted at the 10% significance level. What is the z-score closest to zero in the list that will result in rejection of the null hypothesis?

Accepted Answer

A)  1.19 
B)  -1.54 
C)  -1.84 
D)  2.59 
A)  1.19 
B)  -1.54 
C)  -1.84 
D)  2.59

Question 8

A researcher wants to check the claim that convicted burglars spend an average of 18.7 months in jail. She takes a random sample of 35 such cases from court files and finds that $\bar{x}$= 16.7 months. Assume that the population standard deviation is 7 months. Test the null hypothesis that µ = 18.7 at the 0.05 significance level.

Accepted Answer

A)  Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months is supported. 
B)  Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months cannot be supported. 
C)  Reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months is supported. 
D)  Reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months cannot be supported. 
A)  Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months is supported. 
B)  Do not reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months cannot be supported. 
C)  Reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months is supported. 
D)  Reject the null hypothesis and conclude that the claim that the mean is different from 18.7 months cannot be supported.

Question 9

A right-tailed test is conducted at the 5% significance level. Which of the following z-scores is the smallest one in absolute value that leads to rejection of the null hypothesis?

Accepted Answer

A)  1.61 
B)  1.85 
C)  -1.98 
D)  -2.06 
A)  1.61 
B)  1.85 
C)  -1.98 
D)  -2.06

Question 10

A psychologist claims that more than 19 percent of the population suffers from professional problems due to extreme shyness. Assume that a hypothesis test of the claim has been conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population to which the results of
The test apply.

Accepted Answer

A)  The population is all shy workers. 
B)  The population cannot be identified from the description of the study. 
C)  The population is all American workers. 
D)  The population is all American professional workers (doctors, lawyers, CPA's, and the like). 
A)  The population is all shy workers. 
B)  The population cannot be identified from the description of the study. 
C)  The population is all American workers. 
D)  The population is all American professional workers (doctors, lawyers, CPA's, and the like).

Question 11

A psychologist claims that more than 29 percent of the professional population suffers from problems due to extreme shyness. Assuming that a hypothesis test of the claim has been conducted and that the conclusion is failure to reject the null hypothesis, state the conclusion in non-technical terms.

Accepted Answer

A)  There is sufficient evidence to support the claim that the true proportion is less than 29 percent. 
B)  There is not sufficient evidence to support the claim that the true proportion is greater than 29 percent. 
C)  There is sufficient evidence to support the claim that the true proportion is equal to 29 percent. 
D)  There is sufficient evidence to support the claim that the true proportion is greater than 29 percent. 
A)  There is sufficient evidence to support the claim that the true proportion is less than 29 percent. 
B)  There is not sufficient evidence to support the claim that the true proportion is greater than 29 percent. 
C)  There is sufficient evidence to support the claim that the true proportion is equal to 29 percent. 
D)  There is sufficient evidence to support the claim that the true proportion is greater than 29 percent.

Question 12

The principal of a middle school claims that annual incomes of the families of the seventh-graders at his school vary more than the annual incomes of the families of the seventh-graders at a neighboring school, which have variation described by $\sigma = \$ 13,700$ . Assume that a hypothesis test of the claim has
Been conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population to which the results of the test apply.

Accepted Answer

A)  The current seventh graders at the principal's school 
B)  Seventh graders' families at the school with a standard deviation of $13,700 
C)  All of the families of the class of seventh graders at the principal's school 
D)  All seventh graders' families 
A)  The current seventh graders at the principal's school 
B)  Seventh graders' families at the school with a standard deviation of $13,700 
C)  All of the families of the class of seventh graders at the principal's school 
D)  All seventh graders' families

Question 13

$ \mathrm{H}_{\mathrm{a}}: \mu>21.1, \bar{x}=21.5, \sigma=6, \mathrm{n}=100 $; Without computing a P-value, determine whether the alternate hypothesis is supported and give a reason for your conclusion.

Accepted Answer

A)  $ \mathrm{H}_{\mathrm{a}} $ is supported; $ \bar{x} $ is less than 1 standard deviation above the claimed mean. 
B)  $ \mathrm{H}_{\mathrm{a}} $ is supported; $ \bar{x} $ is more than 4 standard deviations above the claimed mean. 
C)  $ \mathrm{H}_{\mathrm{a}} $ is not supported; $ \bar{x} $ is less than 1 standard deviation above the claimed mean. 
D)  $ \mathrm{H}_{8} $ is not supported; $ \bar{x} $ is more than 4 standard deviations above the claimed mean. 
A)  $ \mathrm{H}_{\mathrm{a}} $ is supported; $ \bar{x} $ is less than 1 standard deviation above the claimed mean. 
B)  $ \mathrm{H}_{\mathrm{a}} $ is supported; $ \bar{x} $ is more than 4 standard deviations above the claimed mean. 
C)  $ \mathrm{H}_{\mathrm{a}} $ is not supported; $ \bar{x} $ is less than 1 standard deviation above the claimed mean. 
D)  $ \mathrm{H}_{8} $ is not supported; $ \bar{x} $ is more than 4 standard deviations above the claimed mean.

Question 14

$\mathrm{z}=-1.5 \text { for } \mathrm{H}_{\mathrm{a}}: \mu \neq \text {claimed value; What is the P-value for the test? }$

Accepted Answer

A)  0.0668 
B)  0.1336 
C)  0.8664 
D)  0.9332 
E)  None of the above 
A)  0.0668 
B)  0.1336 
C)  0.8664 
D)  0.9332 
E)  None of the above

Question 15

The owner of a football team claims that the average attendance at home games is over 4000, and he is therefore justified in moving the team to a city with a larger stadium. Assume that a hypothesis test of the claim has been conducted and that the conclusion of the test was to reject the null hypothesis.
Identify the population to which the results of the test apply.

Accepted Answer

A)  All games played by the team in question in which the attendance is over 4000 
B)  All future home games to be played by the team in question 
C)  All home games played by the team in question 
D)  None of the populations given are appropriate. 
A)  All games played by the team in question in which the attendance is over 4000 
B)  All future home games to be played by the team in question 
C)  All home games played by the team in question 
D)  None of the populations given are appropriate.

Question 16

A supplier of DVDs claims that no more than 1% of the DVDs are defective. In a random sample of 600 DVDs, it is found that 3% are defective, but the supplier claims that this is only a sample fluctuation. At the 0.01 level of significance, test the supplier's claim that no more than 1% are defective.

Accepted Answer

A)  Do not reject the null hypothesis and conclude that there is evidence to support the claim that more than 1% of the DVDs are defective. 
B)  Reject the null hypothesis and conclude that there is insufficient evidence to support the claim that more than 1% of the DVDs are defective. 
C)  Do not reject the null hypothesis and conclude that there is insufficient evidence to support the claim that more than 1% of the DVDs are defective. 
D)  Reject the null hypothesis and conclude that there is sufficient evidence to support the claim that more than 1% of the DVDs are defective. 
A)  Do not reject the null hypothesis and conclude that there is evidence to support the claim that more than 1% of the DVDs are defective. 
B)  Reject the null hypothesis and conclude that there is insufficient evidence to support the claim that more than 1% of the DVDs are defective. 
C)  Do not reject the null hypothesis and conclude that there is insufficient evidence to support the claim that more than 1% of the DVDs are defective. 
D)  Reject the null hypothesis and conclude that there is sufficient evidence to support the claim that more than 1% of the DVDs are defective.

Question 17

At one school, the average amount of time that tenth-graders spend watching television each week is 21 hours. The principal introduces a campaign to encourage the students to watch less television. One year later, the principal wants to perform a hypothesis test to determine whether the average amount of time spent watching television per week has decreased. The hypotheses are: $$\begin{array} { l } 
\mathrm { H } _ { 0 } : \mu = 21 \text { hours } \
\mathrm { H } _ { \mathrm { a } } : \mu < 21 \text { hours }
\end{array}$$ Suppose that the results of the sampling lead to non-rejection of the null hypothesis. Classify that conclusion as a Type I error, a Type II error, or a correct decision, if in fact the mean amount of time, ?, spent watching television has increased.

Accepted Answer

A)  Type I error 
B)  Correct decision 
C)  Type II error 
A)  Type I error 
B)  Correct decision 
C)  Type II error

Question 18

$$\mathrm { z } = 1.8 \text { for } \mathrm { H } _ { \mathrm { a } } : \mu > \text { claimed value. What is the P-value for the test? }$$

Accepted Answer

A)  0.9641 
B)  3.59 
C)  96.41 
D)  0.0359 
E)  None of the above 
A)  0.9641 
B)  3.59 
C)  96.41 
D)  0.0359 
E)  None of the above

Question 19

A study of a brand of "in the shell peanuts" gives the following results: $$\begin{array} { c | c } 
\begin{array} { l } 
\text { Number of } \
\text { Peanuts per bag }
\end{array} & \text { Probability } \
\hline 25 & 0.003 \
30 & 0.020 \
35 & 0.090 \
40 & 0.150 \
45 & 0.450 \
50 & 0.217 \
55 & 0.070
\end{array}$$ A significant event at the 0.10 level is a fan getting a bag with how many peanuts?

Accepted Answer

A)  25 or 30 or 35 peanuts 
B)  25 or 55 peanuts 
C)  35 or 45 or 50 peanuts 
D)  None of the selections are correct. 
A)  25 or 30 or 35 peanuts 
B)  25 or 55 peanuts 
C)  35 or 45 or 50 peanuts 
D)  None of the selections are correct.

Question 20

A random sample of 139 forty-year-old men contains 26% smokers. Use Table 5.1 to estimate the P- value for a test of the claim that the percentage of forty-year-old men that smoke is 22%.

Accepted Answer

A)  0.2542 
B)  0.1401 
C)  0.2802 
D)  0.1271 
A)  0.2542 
B)  0.1401 
C)  0.2802 
D)  0.1271

A two-tailed test is conducted at the 5% significance level. Which of the z-scores below is the smallest one that leads to rejection of the null hypothesis?

A researcher claims that more than 62% of voters favor gun control. State the null hypothesis and the alternative hypothesis for a test of significance.

A consumer group claims that the mean running time for a certain type of flashlight battery is not the same as the manufacturer's claims. Determine the null and alternative hypotheses for the test Described.

A two-tailed test is conducted at the 10% significance level. What is the z-score closest to zero in the list that will result in rejection of the null hypothesis?

A right-tailed test is conducted at the 5% significance level. Which of the following z-scores is the smallest one in absolute value that leads to rejection of the null hypothesis?

A psychologist claims that more than 29 percent of the professional population suffers from problems due to extreme shyness. Assuming that a hypothesis test of the claim has been conducted and that the conclusion is failure to reject the null hypothesis, state the conclusion in non-technical terms.

$\mathrm{H}_{\mathrm{a}}: \mu>21.1, \bar{x}=21.5, \sigma=6, \mathrm{n}=100$ ; Without computing a P-value, determine whether the alternate hypothesis is supported and give a reason for your conclusion.

$\mathrm{z}=-1.5 \text { for } \mathrm{H}_{\mathrm{a}}: \mu \neq \text {claimed value; What is the P-value for the test? }$

$\mathrm { z } = 1.8 \text { for } \mathrm { H } _ { \mathrm { a } } : \mu > \text { claimed value. What is the P-value for the test? }$

A study of a brand of "in the shell peanuts" gives the following results: Number of Peanuts per bag Probability 25 0.003 30 0.020 35 0.090 40 0.150 45 0.450 50 0.217 55 0.070 A significant event at the 0.10 level is a fan getting a bag with how many peanuts?

A random sample of 139 forty-year-old men contains 26% smokers. Use Table 5.1 to estimate the P- value for a test of the claim that the percentage of forty-year-old men that smoke is 22%.

Speaking of Statistics

Measurement in Statistics

Visual Displays of Data Exam

Describing Data

A Normal World

Probability in Statistics

From Samples to Populations

T Tests, Two-Way Tables, and Anova

Filters

Exam 9: Hypothesis Testing

A two-tailed test is conducted at the 5% significance level. Which of the z-scores below is the smallest one that leads to rejection of the null hypothesis?

A researcher claims that more than 62% of voters favor gun control. State the null hypothesis and the alternative hypothesis for a test of significance.

A consumer group claims that the mean running time for a certain type of flashlight battery is not the same as the manufacturer's claims. Determine the null and alternative hypotheses for the test Described.

A two-tailed test is conducted at the 10% significance level. What is the z-score closest to zero in the list that will result in rejection of the null hypothesis?

A right-tailed test is conducted at the 5% significance level. Which of the following z-scores is the smallest one in absolute value that leads to rejection of the null hypothesis?

A psychologist claims that more than 29 percent of the professional population suffers from problems due to extreme shyness. Assuming that a hypothesis test of the claim has been conducted and that the conclusion is failure to reject the null hypothesis, state the conclusion in non-technical terms.

Ha:μ>21.1,xˉ=21.5,σ=6,n=100 \mathrm{H}_{\mathrm{a}}: \mu>21.1, \bar{x}=21.5, \sigma=6, \mathrm{n}=100 Ha​:μ>21.1,xˉ=21.5,σ=6,n=100 ; Without computing a P-value, determine whether the alternate hypothesis is supported and give a reason for your conclusion.

z=−1.5 for Ha:μ≠claimed value; What is the P-value for the test? \mathrm{z}=-1.5 \text { for } \mathrm{H}_{\mathrm{a}}: \mu \neq \text {claimed value; What is the P-value for the test? }z=−1.5 for Ha​:μ=claimed value; What is the P-value for the test?

z=1.8 for Ha:μ> claimed value. What is the P-value for the test? \mathrm { z } = 1.8 \text { for } \mathrm { H } _ { \mathrm { a } } : \mu > \text { claimed value. What is the P-value for the test? }z=1.8 for Ha​:μ> claimed value. What is the P-value for the test?

A study of a brand of "in the shell peanuts" gives the following results: Number of Peanuts per bag Probability 25 0.003 30 0.020 35 0.090 40 0.150 45 0.450 50 0.217 55 0.070 A significant event at the 0.10 level is a fan getting a bag with how many peanuts?

A random sample of 139 forty-year-old men contains 26% smokers. Use Table 5.1 to estimate the P- value for a test of the claim that the percentage of forty-year-old men that smoke is 22%.

Speaking of Statistics

Measurement in Statistics

Visual Displays of Data Exam

Describing Data

A Normal World

Probability in Statistics

From Samples to Populations

T Tests, Two-Way Tables, and Anova

Filters

$\mathrm{H}_{\mathrm{a}}: \mu>21.1, \bar{x}=21.5, \sigma=6, \mathrm{n}=100$ ; Without computing a P-value, determine whether the alternate hypothesis is supported and give a reason for your conclusion.

$\mathrm{z}=-1.5 \text { for } \mathrm{H}_{\mathrm{a}}: \mu \neq \text {claimed value; What is the P-value for the test? }$

$\mathrm { z } = 1.8 \text { for } \mathrm { H } _ { \mathrm { a } } : \mu > \text { claimed value. What is the P-value for the test? }$