Question 1

An entomologist writes an article in a scientific journal which claims that fewer than 17% of male fireflies are unable to produce light due to a genetic mutation.

Accepted Answer

A)  $H _ { 0 } : p  0.17 , H _ { A } : p = 0.17$ 
C)  $H _ { 0 } : p = 0.17 , H _ { A } : p  0.17 , H _ { A } : p  0.17$ 
A)  $H _ { 0 } : p  0.17 , H _ { A } : p = 0.17$ 
C)  $H _ { 0 } : p = 0.17 , H _ { A } : p  0.17 , H _ { A } : p  0.17$ C

Question 2

A pharmaceutical company wants to answer the question whether it takes longer than 45 seconds for a drug in pill form to dissolve in the gastric juices of the stomach.A sample was taken from patients taken the given drug in pill form and times for the pills to be dissolved were measured.State the hypotheses to test this question.

Accepted Answer

A)  $H _ { 0 } : \mu = 45 \mathrm { sec } ; H _ { A } : \mu \leq 45 \mathrm { sec }$ 
B)  $H _ { 0 } : \mu  45 \mathrm { sec }$ 
D)  $H _ { 0 } : \mu \geq 45 \mathrm { sec } ; H _ { A } : \mu  45 \mathrm { sec } ; H _ { A } : \mu \leq 45 \mathrm { sec }$ 
A)  $H _ { 0 } : \mu = 45 \mathrm { sec } ; H _ { A } : \mu \leq 45 \mathrm { sec }$ 
B)  $H _ { 0 } : \mu  45 \mathrm { sec }$ 
D)  $H _ { 0 } : \mu \geq 45 \mathrm { sec } ; H _ { A } : \mu  45 \mathrm { sec } ; H _ { A } : \mu \leq 45 \mathrm { sec }$ C

Question 3

A mayor is concerned about the percentage of city residents who express disapproval of his job performance.His political committee pays for a newspaper ad, hoping that it will keep the disapproval rate below 12%.They will use a follow-up poll to assess the ad's
Effectiveness.

Accepted Answer

A) $H _ { 0 } : p = 0.12 , H _ { A } : p > 0.12$ B) $H _ { 0 } : p > 0.12 , H _ { A } : p = 0.12$ C) $H _ { 0 } : p > 0.12 , H _ { A } : p < 0.12$ D) $H _ { 0 } : p = 0.12 , H _ { A } : p < 0.12$ E) $H _ { 0 } : p < 0.12 , H _ { A } : p = 0.12$ A) $H _ { 0 } : p = 0.12 , H _ { A } : p > 0.12$ B) $H _ { 0 } : p > 0.12 , H _ { A } : p = 0.12$ C) $H _ { 0 } : p > 0.12 , H _ { A } : p < 0.12$ D) $H _ { 0 } : p = 0.12 , H _ { A } : p < 0.12$ E) $H _ { 0 } : p < 0.12 , H _ { A } : p = 0.12$ D

Question 4

The owner of a football team claims that the average attendance at games is over 74,900, and he is therefore justified in moving the team to a city with a larger stadium.An independent investigator will conduct a hypothesis test to determine whether his claim is accurate.

Accepted Answer

A) Lower-tailed 
B) Upper-tailed 
C) Two-sided 
A) Lower-tailed 
B) Upper-tailed 
C) Two-sided

Question 5

Use the $t$-tables, software, or a calculator to estimate the indicated $P$-value: $P$-value for $t \leq 1.76$ with 24 degrees of freedom

Accepted Answer

A)  $0.0456$ 
B)  $0.0228$ 
C)  $0.9544$ 
D)  $0.9088$ 
E)  $0.9772$ 
A)  $0.0456$ 
B)  $0.0228$ 
C)  $0.9544$ 
D)  $0.9088$ 
E)  $0.9772$

Question 6

A report on the U.S. economy indicates that $28 \%$ of Americans have experienced difficulty in making mortgage payments. A news organization randomly sampled 400 Americans from 10 cities named the "fastest dying cities in the U.S." (Forbes Magazine, August 2008) and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? The $P$-value associated with the test statistic for testing this claim is $0.0029$. At $\alpha = .05$,

Accepted Answer

A)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is equal to $28 \%$. 
B)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is not significantly different from $28 \%$. 
C)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is significantly lower than $28 \%$. 
D)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is significantly higher than $28 \%$. 
E)  None of these 
A)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is equal to $28 \%$. 
B)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is not significantly different from $28 \%$. 
C)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is significantly lower than $28 \%$. 
D)  We can conclude that the percentage of Americans in these cities experiencing difficulty making mortgage payments is significantly higher than $28 \%$. 
E)  None of these

Question 7

The manufacturer of a refrigerator system produces refrigerators that are supposed to maintain a true mean temperature, ?, of 48°F, ideal for certain beverages.The owner of a beverage company does not agree with the refrigerator manufacturer, and will conduct a hypothesis test to determine whether the true mean temperature differs from this value.

Accepted Answer

A) Two-sided 
B) Upper-tailed 
C) Lower-tailed 
A) Two-sided 
B) Upper-tailed 
C) Lower-tailed

Question 8

Data in 1980 showed that about 40% of the adult population had never smoked cigarettes.In 2004, a national health survey interviewed a random sample of 2000 adults and found that 50% had never been smokers.Create a 95% confidence interval for the proportion of adults (in 2004) who had never been smokers.

Accepted Answer

A) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 47.8% and 52.2%. 
B) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 37.4% and 52.2%. 
C) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 47.8% and 58.2%. 
D) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 40% and 60%. 
E) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 47.8% and 63.2%. 
A) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 47.8% and 52.2%. 
B) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 37.4% and 52.2%. 
C) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 47.8% and 58.2%. 
D) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 40% and 60%. 
E) Based on the data, we are 95% confident the proportion of adults in 2004 who had never smoked cigarettes is between 47.8% and 63.2%.

Question 9

In the past, the mean running time for a certain type of flashlight battery has been 8.5 hours.
The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean running time has changed as a result.

Accepted Answer

A) Lower-tailed 
B) Upper-tailed 
C) Two-sided 
A) Lower-tailed 
B) Upper-tailed 
C) Two-sided

Question 10

A pharmaceutical company wants to answer the question whether it takes longer than 45 seconds for a drug in pill form to dissolve in the gastric juices of the stomach.A sample was taken from patients taken the given drug in pill form and times for the pills to be dissolved were measured.State assumptions of the test.
I.The subjects must be part of a medical study group investigating the drug.
II.The subjects in the sample must be randomly selected from a population.
III.The sample data must come from a normally distributed population of observations for
The variable under study.

Accepted Answer

A) I only 
B) II only 
C) III only 
D) II and III 
E) None of these 
A) I only 
B) II only 
C) III only 
D) II and III 
E) None of these

Question 11

Using the t-tables, software, or a calculator, estimate the critical value of t for the given Confidence interval and degrees of freedom: 98% confidence interval with df = 20

Accepted Answer

A) 2.518 
B) 2.539 
C) 2.330 
D) 1.325 
E) 2.528 
A) 2.518 
B) 2.539 
C) 2.330 
D) 1.325 
E) 2.528

Question 12

A report on the U.S. economy indicates that $28 \%$ of Americans have experienced difficulty in making mortgage payments. A news organization randomly sampled 400 Americans from 10 cities named the "fastest dying cities in the U.S." (Forbes Magazine, August 2008) and found that 136 reported such difficulty. Does this indicate that the problem is more severe among these cities? The correct null and alternative hypotheses for testing this claim are

Accepted Answer

A)  $H _ { 0 } : p = 0.28$ and $H _ { A } : p  0.28$ 
C)  $H _ { 0 } : p \neq 0.28$ and $H _ { A } : p = 0.28$ 
D)  $H _ { 0 } : p > 0.28$ and $H _ { A } : p = 0.28$ 
E)  $H _ { 0 } : p = 0.28$ and $H _ { A } : p \neq 0.28$ 
A)  $H _ { 0 } : p = 0.28$ and $H _ { A } : p  0.28$ 
C)  $H _ { 0 } : p \neq 0.28$ and $H _ { A } : p = 0.28$ 
D)  $H _ { 0 } : p > 0.28$ and $H _ { A } : p = 0.28$ 
E)  $H _ { 0 } : p = 0.28$ and $H _ { A } : p \neq 0.28$

Question 13

Use the $t$-tables, software, or a calculator to estimate the indicated $P$-value: $P$-value for $t \geq 1.76$ with 24 degrees of freedom

Accepted Answer

A)  $0.0456$ 
B)  $0.9544$ 
C)  $0.0228$ 
D)  $0.0592$ 
E)  $0.0912$ 
A)  $0.0456$ 
B)  $0.9544$ 
C)  $0.0228$ 
D)  $0.0592$ 
E)  $0.0912$

Question 14

Using the t-tables, software, or a calculator, estimate the critical value of t for the given confidence interval and degrees of freedom: 99% confidence interval with df = 24

Accepted Answer

A) 2.492 
B) 2.797 
C) 2.807 
D) 2.779 
E) 1.711 
A) 2.492 
B) 2.797 
C) 2.807 
D) 2.779 
E) 1.711

Question 15

A manufacturer claims that the mean amount of juice in its 16 ounce bottles are 16.1 ounces.
A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this.

Accepted Answer

A) Lower-tailed 
B) Two-sided 
C) Upper-tailed 
A) Lower-tailed 
B) Two-sided 
C) Upper-tailed

Question 16

A statistician consulting for a state department of transportation conducts a study to see if the proportion of drivers who are intoxicated has decreased since last year. 
$H _ { 0 }$ : The proportion is the same as last year
$H _ { A } :$ The proportion is less than last year.
The P-value of a significance test is greater than the significance level.She can conclude:

Accepted Answer

A) the alternative hypothesis is true. 
B) the null hypothesis is true. 
C) there is not enough evidence to reject the null hypothesis. 
D) the test was too powerful. 
A) the alternative hypothesis is true. 
B) the null hypothesis is true. 
C) there is not enough evidence to reject the null hypothesis. 
D) the test was too powerful.

Question 17

A skeptical paranormal researcher claims that the proportion of Americans that have seen a UFO is less than 5%.

Accepted Answer

A)  $H _ { 0 } : p  0.05$ 
C)  $H _ { 0 } : p > 0.05 , H _ { A } : p = 0.05$ 
D)  $H _ { 0 } : p = 0.05 , H _ { A } : p  0.05$ 
A)  $H _ { 0 } : p  0.05$ 
C)  $H _ { 0 } : p > 0.05 , H _ { A } : p = 0.05$ 
D)  $H _ { 0 } : p = 0.05 , H _ { A } : p  0.05$

An entomologist writes an article in a scientific journal which claims that fewer than 17% of male fireflies are unable to produce light due to a genetic mutation.

A mayor is concerned about the percentage of city residents who express disapproval of his job performance.His political committee pays for a newspaper ad, hoping that it will keep the disapproval rate below 12%.They will use a follow-up poll to assess the ad's Effectiveness.

The owner of a football team claims that the average attendance at games is over 74,900, and he is therefore justified in moving the team to a city with a larger stadium.An independent investigator will conduct a hypothesis test to determine whether his claim is accurate.

Use the $t$ -tables, software, or a calculator to estimate the indicated $P$ -value: $P$ -value for $t \leq 1.76$ with 24 degrees of freedom

In the past, the mean running time for a certain type of flashlight battery has been 8.5 hours. The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean running time has changed as a result.

Using the t-tables, software, or a calculator, estimate the critical value of t for the given Confidence interval and degrees of freedom: 98% confidence interval with df = 20

Use the $t$ -tables, software, or a calculator to estimate the indicated $P$ -value: $P$ -value for $t \geq 1.76$ with 24 degrees of freedom

Using the t-tables, software, or a calculator, estimate the critical value of t for the given confidence interval and degrees of freedom: 99% confidence interval with df = 24

A manufacturer claims that the mean amount of juice in its 16 ounce bottles are 16.1 ounces. A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this.

A skeptical paranormal researcher claims that the proportion of Americans that have seen a UFO is less than 5%.

Stats Starts Here

Displaying and Describing Data

Relationships Between Categorical Variablescontingency Tables

Understanding and Comparing Distributions

The Standard Deviation As a Ruler and the Normal Model

Scatterplots, Association, and Correlation

Linear Regression

Regression Wisdom

Multiple Regression

Sample Surveys

Experiments and Observational Studies

From Randomness to Probability

Sampling Distribution Models and Confidence Intervals for Proportions

Confidence Intervals for Means

More About Tests and Intervals

Comparing Groupspaired

Samples and Blocks

Comparing Counts

Filters

Exam 15: Testing Hypotheses

An entomologist writes an article in a scientific journal which claims that fewer than 17% of male fireflies are unable to produce light due to a genetic mutation.

A mayor is concerned about the percentage of city residents who express disapproval of his job performance.His political committee pays for a newspaper ad, hoping that it will keep the disapproval rate below 12%.They will use a follow-up poll to assess the ad's Effectiveness.

The owner of a football team claims that the average attendance at games is over 74,900, and he is therefore justified in moving the team to a city with a larger stadium.An independent investigator will conduct a hypothesis test to determine whether his claim is accurate.

Use the ttt -tables, software, or a calculator to estimate the indicated PPP -value: PPP -value for t≤1.76t \leq 1.76t≤1.76 with 24 degrees of freedom

In the past, the mean running time for a certain type of flashlight battery has been 8.5 hours. The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean running time has changed as a result.

Using the t-tables, software, or a calculator, estimate the critical value of t for the given Confidence interval and degrees of freedom: 98% confidence interval with df = 20

Use the ttt -tables, software, or a calculator to estimate the indicated PPP -value: PPP -value for t≥1.76t \geq 1.76t≥1.76 with 24 degrees of freedom

Using the t-tables, software, or a calculator, estimate the critical value of t for the given confidence interval and degrees of freedom: 99% confidence interval with df = 24

A manufacturer claims that the mean amount of juice in its 16 ounce bottles are 16.1 ounces. A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this.

A skeptical paranormal researcher claims that the proportion of Americans that have seen a UFO is less than 5%.

Stats Starts Here

Displaying and Describing Data

Relationships Between Categorical Variablescontingency Tables

Understanding and Comparing Distributions

The Standard Deviation As a Ruler and the Normal Model

Scatterplots, Association, and Correlation

Linear Regression

Regression Wisdom

Multiple Regression

Sample Surveys

Experiments and Observational Studies

From Randomness to Probability

Sampling Distribution Models and Confidence Intervals for Proportions

Confidence Intervals for Means

More About Tests and Intervals

Comparing Groupspaired

Samples and Blocks

Comparing Counts

Filters

Use the $t$ -tables, software, or a calculator to estimate the indicated $P$ -value: $P$ -value for $t \leq 1.76$ with 24 degrees of freedom

Use the $t$ -tables, software, or a calculator to estimate the indicated $P$ -value: $P$ -value for $t \geq 1.76$ with 24 degrees of freedom