Question 1

The table t value associated with the upper 5% of the t distribution and 14 degrees of freedom is ___.

Accepted Answer

A)  2.977 
B)  2.624 
C)  2.145 
D)  1.761 
E)  1.345 
A)  2.977 
B)  2.624 
C)  2.145 
D)  1.761 
E)  1.345

Question 2

For a new product, you need to determine the average diameter of a specialized electronic component, which will be a critical component of the new product. You measure the diameter in a sample of size 15 and find an average diameter of 0.24 mm, with a standard deviation of 0.02 mm. Other studies indicate that the diameter of similar products is normally distributed. The 99% confidence interval for the average diameter of this electronic component is ___.

Accepted Answer

A)  0.232 to 0.248 
B)  0.230 to 0.250 
C)  0.228 to 0.252 
D)  0.226 to 0.254 
E)  0.224 to 0.256 
A)  0.232 to 0.248 
B)  0.230 to 0.250 
C)  0.228 to 0.252 
D)  0.226 to 0.254 
E)  0.224 to 0.256

Question 3

In estimating the sample size necessary to estimate π, if there is no good approximation for the value of P available, the value of ___ should be used as an estimate of π in the formula.

Accepted Answer

A)  0.10 
B)  0.50 
C)  0.40 
D)  1.96 
E)  2.00 
A)  0.10 
B)  0.50 
C)  0.40 
D)  1.96 
E)  2.00

Question 4

A random sample of 64 items is selected from a population of 400 items. The sample mean is 200. The population standard deviation is 48. From this data, a 90% confidence interval to estimate the population mean can be computed as ___.

Accepted Answer

A)  189.21 to 210.79 
B)  188.24 to 211.76 
C)  190.13 to 209.87 
D)  190.94 to 209.06 
E)  193.45 to 211.09 
A)  189.21 to 210.79 
B)  188.24 to 211.76 
C)  190.13 to 209.87 
D)  190.94 to 209.06 
E)  193.45 to 211.09

Question 5

A researcher wants to estimate the percent of the population that uses the radio to stay informed on local news issues. The researcher wants to estimate the population proportion with a 90% level of confidence. He estimates from previous studies that no more than 30% of the population stay informed on local issues through the radio. The researcher wants the estimate to have an error of no more than.02. The necessary sample size is at least ___.

Accepted Answer

A)  29 
B)  47 
C)  298 
D)  1421 
E)  1500 
A)  29 
B)  47 
C)  298 
D)  1421 
E)  1500

Question 6

James Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks. His staff randomly selected personnel files for 100 tellers in the Southeast Region and determined that their mean training time was 25 hours. Assume that the population standard deviation is 5 hours. The 95% confidence interval for the population mean of training times is ___.

Accepted Answer

A)  15.20 to 34.80 
B)  24.18 to 25.82 
C)  24.02 to 25.98 
D)  16.78 to 33.23 
E)  23.32 to 35.46 
A)  15.20 to 34.80 
B)  24.18 to 25.82 
C)  24.02 to 25.98 
D)  16.78 to 33.23 
E)  23.32 to 35.46

Question 7

Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS email for non-business communications. A random sample of 200 email messages was selected. Thirty of the messages were $\textbf{       not  }$  business related. The 95% confidence interval for the population proportion is ___.

Accepted Answer

A)  0.108 to 0.192 
B)  0.153 to 0.247 
C)  0.091 to 0.209 
D)  0.101 to 0.199 
E)  0.199 to 0.201 
A)  0.108 to 0.192 
B)  0.153 to 0.247 
C)  0.091 to 0.209 
D)  0.101 to 0.199 
E)  0.199 to 0.201

Question 8

A large trucking company wants to estimate the proportion of its tracker truck population with refrigerated carrier capacity. A random sample of 200 tracker trucks is taken and 30% of the sample have refrigerated carrier capacity. The 95% confidence interval to estimate the population proportion is ___.

Accepted Answer

A)  0.53 to 0.67 
B)  0.25 to 0.35 
C)  0.24 to 0.36 
D)  0.27 to 0.33 
E)  0.28 to 0.34 
A)  0.53 to 0.67 
B)  0.25 to 0.35 
C)  0.24 to 0.36 
D)  0.27 to 0.33 
E)  0.28 to 0.34

Question 9

If the degrees of freedom in a t distribution increase, difference between the t values and the z values will also increase.

Accepted Answer

A) True 
 B)False

Question 10

Given the error we are willing to tolerate, the sample size is determined by the mean µ of the population and the confidence level.

Accepted Answer

A) True 
 B)False

Question 11

A large trucking company wants to estimate the proportion of its tracker truck population with refrigerated carrier capacity. A random sample of 200 tracker trucks is taken and 30% of the sample have refrigerated carrier capacity. The 90% confidence interval to estimate the population proportion is ___.

Accepted Answer

A)  0.53 to 0.67 
B)  0.25 to 0.35 
C)  0.24 to 0.36 
D)  0.27 to 0.33 
E)  0.33 to 0.39 
A)  0.53 to 0.67 
B)  0.25 to 0.35 
C)  0.24 to 0.36 
D)  0.27 to 0.33 
E)  0.33 to 0.39

Question 12

If the population is $\textbf{     not    }$  normal but its standard deviation σ is known, and the sample size n is large (n ≥ 30), z distribution values may be used to determine interval estimates for the population mean.

Accepted Answer

A) True 
 B)False

Question 13

A researcher wants to estimate the proportion of manufacturing companies that use the Six Sigma method. For this purpose, she will take a random sample of 50 manufacturing companies and find out how many of them use this method. She estimates that the proportion will be anywhere from 0.4 to 0.55. Of all these proportions, which one would produce the widest 95% confidence interval for the population proportion?

Accepted Answer

A)  0.4 
B)  0.45 
C)  0.5 
D)  0.55 
E)  0.6 
A)  0.4 
B)  0.45 
C)  0.5 
D)  0.55 
E)  0.6

Question 14

Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS email for non-business communications. He plans to use a 95% confidence interval estimate of the proportion of email messages that are non-business; he will accept a 0.05 error. Previous studies indicate that approximately 30% of employee email is $\textbf{     not    }$  business related. Elwin should sample ___ email messages.

Accepted Answer

A)  323 
B)  12 
C)  457 
D)  14 
E)  100 
A)  323 
B)  12 
C)  457 
D)  14 
E)  100

Question 15

Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS email for non-business communications. He plans to use a 98% confidence interval estimate of the proportion of email messages that are non-business; he will accept a 0.05 error. Previous studies indicate that approximately 30% of employee email is $\textbf{      not  }$  business related. Elwin should sample ___ email messages.

Accepted Answer

A)  323 
B)  12 
C)  457 
D)  14 
E)  100 
A)  323 
B)  12 
C)  457 
D)  14 
E)  100

Question 16

A researcher wants to estimate the proportion of the population which possesses a given characteristic. A random sample of size 1800 is taken resulting in 450 items which possess the characteristic. The point estimate for this population proportion is ___.

Accepted Answer

A)  0.55 
B)  0.45 
C)  0.35 
D)  0.25 
E)  0.15 
A)  0.55 
B)  0.45 
C)  0.35 
D)  0.25 
E)  0.15

Question 17

The z value associated with a two?sided 88% confidence interval is ___.

Accepted Answer

A)  1.28 
B)  1.55 
C)  1.17 
D)  0.88 
E)  1.90 
A)  1.28 
B)  1.55 
C)  1.17 
D)  0.88 
E)  1.90

Question 18

A researcher wants to estimate the proportion of millennials who regularly listen to podcasts (defined as at least two entire podcasts per week). Previous studies indicate that only 18% of millennials listen regularly to podcasts, and this researcher wants to estimate if that figure has increased. For this purpose, the researcher will use a 98% confidence level and wants to estimate the population proportion within 0.01 (i.e., 1 percentage point) of the actual value. The required sample size is at least ___.

Accepted Answer

A)  47 
B)  48 
C)  320 
D)  321 
E)  331 
A)  47 
B)  48 
C)  320 
D)  321 
E)  331

Question 19

You are thinking of using a t table to find a 95 percent confidence interval for the mean μ of a population. The distribution of the population is normal and the population standard deviation is unknown. A random sample of size n is drawn from this population. You may use the t distribution only if the sample size n is small.

Accepted Answer

A) True 
 B)False

Question 20

A sample of 120 adults from a large population has a mean IQ of 112 with a standard deviation of 10. Construct a 98% confidence interval for the true mean IQ of the population.

Accepted Answer

The answer of A sample of 120 adults from a...

The table t value associated with the upper 5% of the t distribution and 14 degrees of freedom is ___.

In estimating the sample size necessary to estimate π, if there is no good approximation for the value of P available, the value of ___ should be used as an estimate of π in the formula.

A random sample of 64 items is selected from a population of 400 items. The sample mean is 200. The population standard deviation is 48. From this data, a 90% confidence interval to estimate the population mean can be computed as ___.

Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS email for non-business communications. A random sample of 200 email messages was selected. Thirty of the messages were $\textbf{ not }$ business related. The 95% confidence interval for the population proportion is ___.

If the degrees of freedom in a t distribution increase, difference between the t values and the z values will also increase.

Given the error we are willing to tolerate, the sample size is determined by the mean µ of the population and the confidence level.

If the population is $\textbf{ not }$ normal but its standard deviation σ is known, and the sample size n is large (n ≥ 30), z distribution values may be used to determine interval estimates for the population mean.

A researcher wants to estimate the proportion of the population which possesses a given characteristic. A random sample of size 1800 is taken resulting in 450 items which possess the characteristic. The point estimate for this population proportion is ___.

The z value associated with a two?sided 88% confidence interval is ___.

A sample of 120 adults from a large population has a mean IQ of 112 with a standard deviation of 10. Construct a 98% confidence interval for the true mean IQ of the population.

Introduction to Statistics

Organizing and Visualizing Data

Descriptive Statistics

Gathering Data

Probability

Decision Analysis and Expected Value

Discrete Probability Distributions

Continuous Distributions

Sampling Distributions

Hypothesis Testing for Single Populations

Hypothesis Testing for Two Populations

Analysis of Variance Anova

Linear Correlation and Simple Linear Regression Analysis

Categorical Versus Categorical: Tests

Filters

Exam 10: Confidence Intervals

The table t value associated with the upper 5% of the t distribution and 14 degrees of freedom is ___.

In estimating the sample size necessary to estimate π, if there is no good approximation for the value of P available, the value of ___ should be used as an estimate of π in the formula.

A random sample of 64 items is selected from a population of 400 items. The sample mean is 200. The population standard deviation is 48. From this data, a 90% confidence interval to estimate the population mean can be computed as ___.

Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS email for non-business communications. A random sample of 200 email messages was selected. Thirty of the messages were not \textbf{ not } not business related. The 95% confidence interval for the population proportion is ___.

If the degrees of freedom in a t distribution increase, difference between the t values and the z values will also increase.

Given the error we are willing to tolerate, the sample size is determined by the mean µ of the population and the confidence level.

If the population is not \textbf{ not } not normal but its standard deviation σ is known, and the sample size n is large (n ≥ 30), z distribution values may be used to determine interval estimates for the population mean.

A researcher wants to estimate the proportion of the population which possesses a given characteristic. A random sample of size 1800 is taken resulting in 450 items which possess the characteristic. The point estimate for this population proportion is ___.

The z value associated with a two?sided 88% confidence interval is ___.

A sample of 120 adults from a large population has a mean IQ of 112 with a standard deviation of 10. Construct a 98% confidence interval for the true mean IQ of the population.

Introduction to Statistics

Organizing and Visualizing Data

Descriptive Statistics

Gathering Data

Probability

Decision Analysis and Expected Value

Discrete Probability Distributions

Continuous Distributions

Sampling Distributions

Hypothesis Testing for Single Populations

Hypothesis Testing for Two Populations

Analysis of Variance Anova

Linear Correlation and Simple Linear Regression Analysis

Categorical Versus Categorical: Tests

Filters

Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS email for non-business communications. A random sample of 200 email messages was selected. Thirty of the messages were $\textbf{ not }$ business related. The 95% confidence interval for the population proportion is ___.

If the population is $\textbf{ not }$ normal but its standard deviation σ is known, and the sample size n is large (n ≥ 30), z distribution values may be used to determine interval estimates for the population mean.