Question 1

A major electronics store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following results: $\bar { x }$ = $50.50 and s2 = 400. A 95% confidence interval for the average amount the credit card customers spent on their first visit to the chain's new store in the mall is:

Accepted Answer

A) $50.50 $\pm$ $9.09. 
B) $50.50 $\pm$ $10.12. 
C) $50.50 $\pm$ $11.08. 
D) None of these choices.

Question 2

The t-distribution is used to develop a confidence interval estimate of the population mean when the population standard deviation is unknown.

Accepted Answer

A) True 
 B)False

Question 3

NARRBEGIN: Sinus Drug
Sinus Drug
A company claims that 10% of the users of a certain sinus drug experience drowsiness. In clinical studies of this sinus drug, 81 of the 900 subjects experienced drowsiness
NARREND
-{Sinus Drug Narrative} Construct a 95% confidence interval estimate of the population proportion of the users of this allergy drug who experience drowsiness.

Accepted Answer

The answer of NARRBEGIN: Sinus Drug
Sinus Drug
A company claims that...

Question 4

In order to interpret the p-value associated with hypothesis testing about the population mean $\mu$, it is necessary to know the value of the test statistic.

Accepted Answer

A) True 
 B)False

Question 5

NARRBEGIN: Healthy foods
Healthy Foods
In segmenting the frozen meal market in Spain, a food manufacturer uses health and diet consciousness as the segmentation variable. Four segments are developed and coded as follows:
 1: Concermed about eating healthy faods
2: Concerned about weight
3: Concerned about health because of illnese
4: Unconcermed To distinguish between groups, surveys are conducted. On the basis of a questionnaire, people are categorized as belonging to one of these groups. A recent survey asked a random sample of 1,500 Spanish adults (20 and over) to complete the survey. Out of the 1,500 people surveyed, 360 indicated that they are concerned about eating healthy foods. The most recent information available reveals that there are 40,256,000 Spanish adults who are 20 and over.NARREND
-{Healthy Foods Narrative} Estimate with 95% confidence the proportion p of Spanish adults who classify themselves as concerned about eating healthy.

Accepted Answer

The answer of NARRBEGIN: Healthy foods
Healthy Foods
In segmenting the frozen...

Question 6

NARRBEGIN: Hourly Fees
Hourly Fees
A random sample of 15 hourly fees for car washers (including tips) was drawn from a normal population. The sample mean and sample standard deviation were $\bar { x }$ = $14.9 and s = $6.75.NARREND
-{Hourly Fees Narrative} Can we infer at the 5% significance level that the mean fee for car washers (including tips) is greater than 12?

Accepted Answer

The answer of NARRBEGIN: Hourly Fees
Hourly Fees
A random sample of...

Question 7

Estimating or testing for p is used in situations when the data are ____________________.

Accepted Answer

The answer of Estimating or testing for p is used...

Question 8

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400 and $\hat { p }$ = 0.10, is 0.0247.

Accepted Answer

A) True 
 B)False

Question 9

NARRBEGIN: Tractor Dealership
Tractor Dealership
An accountant was performing an audit for a tractor dealership. An auditor wants to examine the monetary error made by the purchasing order department in the month of July. He decided to randomly sample 100 of the 925 purchase orders for the month of July, and found the amount of error in each one. The statistics for this sample were: $$\bar { x }$$ = $6.0 and s = $17.012.NARREND
-{Tractor Dealership Narrative} Why should the finite population correction factor (FPCF) be used for this problem? Explain.

Accepted Answer

The answer of NARRBEGIN: Tractor Dealership
Tractor Dealership
An accountant was performing...

Question 10

If a sample has 18 observations and a 90% confidence estimate for $\mu$ is needed, the appropriate value of t is 1.740.

Accepted Answer

A) True 
 B)False

Question 11

NARRBEGIN: Socialist Voters
Socialist Party Voters
A pollster in Italy wants to challenge a claim that 5% of the registered voters in his country are Socialists; he thinks the percentage is lower than that. In a test of hypothesis, HS1U1B10S1U1B0: p = 0.05 vs. HS1U1B11S1U1B0: p < 0.05, his random sample of size 1,000 registered voters revealed that the number of Socialists was 40.NARREND
-{Socialist Voters Narrative} Compute the p-value and explain how to use it to test the hypotheses.

Accepted Answer

The answer of NARRBEGIN: Socialist Voters
Socialist Party Voters
A pollster in...

Question 12

A random sample is drawn from a normal distribution with mean $\mu$and variance $\sigma$2. The random variable (n - 1)S2 / $\sigma$2 has a chi-squared probability distribution with n degrees of freedom.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following would be an appropriate alternative hypothesis?

Accepted Answer

A) The population proportion is less than 0.65. 
B) The sample proportion is less than 0.65. 
C) The population proportion is equal to 0.65. 
D) The sample proportion is equal to 0.65.

Question 14

NARRBEGIN: Mystic Pizza
Mystic Pizza
Mystic Pizza in Mystic, Connecticut, advertises that they deliver your pizza within 15 minutes of placing an order or it is free. A sample of 25 customers is selected at random. The average delivery time in the sample was 13 minutes with a sample standard deviation of 4 minutes.NARREND
-{Mystic Pizza Narrative} What is the required condition of the technique used in the previous question?

Accepted Answer

The answer of NARRBEGIN: Mystic Pizza
Mystic Pizza
Mystic Pizza in Mystic,...

Question 15

Assuming that all necessary conditions are met, what needs to be changed in the formula $\tilde { p } \pm t _ { a } \sqrt { \tilde { p } ( 1 - \tilde { p } ) / n }$ so that we can use it to construct a (1 -$\alpha$) confidence interval estimate for the population proportion p?

Accepted Answer

A) should be replaced by p. 
B) t$\alpha$ should be replaced by z$\alpha$. 
C) t$\alpha$should be replaced by t$\alpha$/ 2. 
D) t$\alpha$ should be replaced by z$\alpha$ / 2.

Question 16

____________________ populations allow us to use the confidence interval estimate of a mean to produce a confidence interval estimate of the population total.

Accepted Answer

The answer of ____________________ populations allow us to use the...

Question 17

The t-test for a population mean is ____________________, meaning that if the population is nonnormal, the results of the test and confidence interval are still valid as long as the nonnormality is not extreme.

Accepted Answer

The answer of The t-test for a population mean is...

Question 18

The area to the right of a certain critical value on a chi-squared distribution is 0.025. For 5 degrees of freedom, the critical value is 11.143.

Accepted Answer

A) True 
 B)False

Question 19

Two uses for the population variance are to measure risk and consistency.

Accepted Answer

A) True 
 B)False

Question 20

To produce a confidence interval estimator for the total, we multiply the lower and upper confidence limits of the interval estimator of p by ____________________.

Accepted Answer

The answer of To produce a confidence interval estimator for...

Exam 12: Inference About a Population

The t-distribution is used to develop a confidence interval estimate of the population mean when the population standard deviation is unknown.

In order to interpret the p-value associated with hypothesis testing about the population mean $\mu$ , it is necessary to know the value of the test statistic.

Estimating or testing for p is used in situations when the data are ____________________.

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400 and $\hat { p }$ = 0.10, is 0.0247.

If a sample has 18 observations and a 90% confidence estimate for $\mu$ is needed, the appropriate value of t is 1.740.

A random sample is drawn from a normal distribution with mean $\mu$ and variance $\sigma$ ². The random variable (n - 1)S² / $\sigma$ ²has a chi-squared probability distribution with n degrees of freedom.

Which of the following would be an appropriate alternative hypothesis?

Assuming that all necessary conditions are met, what needs to be changed in the formula $\tilde { p } \pm t _ { a } \sqrt { \tilde { p } ( 1 - \tilde { p } ) / n }$ so that we can use it to construct a (1 - $\alpha$ ) confidence interval estimate for the population proportion p?

____________________ populations allow us to use the confidence interval estimate of a mean to produce a confidence interval estimate of the population total.

The t-test for a population mean is ____________________, meaning that if the population is nonnormal, the results of the test and confidence interval are still valid as long as the nonnormality is not extreme.

The area to the right of a certain critical value on a chi-squared distribution is 0.025. For 5 degrees of freedom, the critical value is 11.143.

Two uses for the population variance are to measure risk and consistency.

To produce a confidence interval estimator for the total, we multiply the lower and upper confidence limits of the interval estimator of p by ____________________.

Exam 12: Inference About a Population

The t-distribution is used to develop a confidence interval estimate of the population mean when the population standard deviation is unknown.

In order to interpret the p-value associated with hypothesis testing about the population mean μ\muμ , it is necessary to know the value of the test statistic.

Estimating or testing for p is used in situations when the data are ____________________.

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400 and p^\hat { p }p^​ = 0.10, is 0.0247.

If a sample has 18 observations and a 90% confidence estimate for μ\muμ is needed, the appropriate value of t is 1.740.

A random sample is drawn from a normal distribution with mean μ\muμ and variance σ\sigmaσ 2. The random variable (n - 1)S2 / σ\sigmaσ 2 has a chi-squared probability distribution with n degrees of freedom.

Which of the following would be an appropriate alternative hypothesis?

____________________ populations allow us to use the confidence interval estimate of a mean to produce a confidence interval estimate of the population total.

The t-test for a population mean is ____________________, meaning that if the population is nonnormal, the results of the test and confidence interval are still valid as long as the nonnormality is not extreme.

The area to the right of a certain critical value on a chi-squared distribution is 0.025. For 5 degrees of freedom, the critical value is 11.143.

Two uses for the population variance are to measure risk and consistency.

To produce a confidence interval estimator for the total, we multiply the lower and upper confidence limits of the interval estimator of p by ____________________.

In order to interpret the p-value associated with hypothesis testing about the population mean $\mu$ , it is necessary to know the value of the test statistic.

The lower limit of the 90% confidence interval for the population proportion p, given that n = 400 and $\hat { p }$ = 0.10, is 0.0247.

If a sample has 18 observations and a 90% confidence estimate for $\mu$ is needed, the appropriate value of t is 1.740.

A random sample is drawn from a normal distribution with mean $\mu$ and variance $\sigma$ ². The random variable (n - 1)S² / $\sigma$ ²has a chi-squared probability distribution with n degrees of freedom.