Summary information is given for the weights (in pounds) of 1000 randomly sampled tractor trailers. \[\begin{array} { l r l r } \text { MIN: } & 4015 & 25 \% : & 5615 \\ \text { MAX: } & 10,615 & 75 \% : & 8615 \\ \text { AVE: } & 7015 & \text { Std. Dev.: } & 1400 \end{array}\] Find the percentage of tractor trailers with weights between 5615 and 8615 pounds.

A) 50% B) 75% C) 25% D) 100% A) 50% B) 75% C) 25% D) 100%

The following data represent the scores of 50 students on a statistics exam. The mean score is 80.02, and the standard deviation is 11.9. \[\begin{array} { l l l l l l l l l l } 39 & 51 & 59 & 63 & 66 & 68 & 68 & 69 & 70 & 71 \\ 71 & 71 & 73 & 74 & 76 & 76 & 76 & 77 & 78 & 79 \\ 79 & 79 & 79 & 80 & 80 & 82 & 83 & 83 & 83 & 85 \\ 85 & 86 & 86 & 88 & 88 & 88 & 88 & 89 & 89 & 89 \\ 90 & 90 & 91 & 91 & 92 & 95 & 96 & 97 & 97 & 98 \end{array}\] What percentage of the scores lies within one standard deviation of the mean? two standard deviations of the mean? three standard deviations of the mean? Based on these percentages, do you believe that the distribution of scores is mound-shaped and symmetric? Explain.

74% of the scores lie within one standar

An annual survey sent to retail store managers contained the question "Did your store suffer any losses due to employee theft?" The responses are summarized in the table for two years. Compare the responses for the two years using side-by-side bar charts. What inferences can be made from the charts? \[\begin{array} { l | c | c } \begin{array} { c } \text { Employee } \\ \text { Theft } \end{array} & \begin{array} { c } \text { Percentage } \\ \text { in year 1 } \end{array} & \begin{array} { c } \text { Percentage } \\ \text { in year 2 } \end{array} \\ \hline \text { Yes } & 34 & 23 \\ \text { No } & 51 & 68 \\ \text { Don't know } & 15 & 9 \\ \text { Totals } & 100 & 100 \end{array}\]

@#IMG-DLM& Losses due to employee theft

Exam 2: Methods for Describing Sets of Data

Your teacher announces that the scores on a test have a mean of 83 points with a standard deviation of 4 points, so it is reasonable to expect that you scored at least 70 on the test.

(True/False)

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Question 141

In general, the sample mean is a better estimator of the population mean for larger sample sizes.

(True/False)

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Question 142

A shoe company reports the mode for the shoe sizes of men's shoes is 12. Interpret this result.

(Multiple Choice)

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Question 143

Chebyshev's rule applies to large data sets, while the empirical rule applies to small data sets.

(True/False)

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Question 144

Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees to program, and you have been requested to review the performance of one of the trainees on the final test that was given to all trainees. The mean and standard deviation of the test scores are 74 and 2, respectively. Assuming nothing is known about the distribution, what percentage of test-takers scored above 80?

(Multiple Choice)

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Question 145

The sample variance and standard deviation can be calculated using only the sum of the data, $\sum { x }$ , and the sample size, n.

(True/False)

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Question 146

Summary information is given for the weights (in pounds) of 1000 randomly sampled tractor trailers. MIN: 4015 25\%: 5615 MAX: 10,615 75\%: 8615 AVE: 7015 Std. Dev.: 1400 Find the percentage of tractor trailers with weights between 5615 and 8615 pounds.

(Multiple Choice)

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Question 147

The z-score for a value x is -2.5. State whether the value of x lies above or below the mean and by how many standard deviations.

(Essay)

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Question 148

The following data represent the scores of 50 students on a statistics exam. The mean score is 80.02, and the standard deviation is 11.9. 39 51 59 63 66 68 68 69 70 71 71 71 73 74 76 76 76 77 78 79 79 79 79 80 80 82 83 83 83 85 85 86 86 88 88 88 88 89 89 89 90 90 91 91 92 95 96 97 97 98 What percentage of the scores lies within one standard deviation of the mean? two standard deviations of the mean? three standard deviations of the mean? Based on these percentages, do you believe that the distribution of scores is mound-shaped and symmetric? Explain.

(Essay)

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Question 149

The top speeds for a sample of five new automobiles are listed below. Calculate the standard deviation of the speeds. Round to four decimal places. 180, 100, 195, 130, 155

(Multiple Choice)

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Question 150

Which expression represents the sum of the squares of the observations in a data set? A) $\sum x ^ { 2 }$ B) $\left( \sum x ^ { 2 } \right) ^ { 2 }$ C) $\sum { \sqrt { x } }$ D) $\sqrt { \sum { x } }$

(Short Answer)

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Question 151

A recent survey was conducted to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a 3-bedroom house using gas or electric energy had a mean of $112 and a standard deviation of $15. Three solar homes reported monthly utility bills of $59, $63, and $64. Which of the following statements is true?

(Multiple Choice)

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Question 152

What class percentage corresponds to a class relative frequency of .37?

(Multiple Choice)

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Question 153

Find the z-score for the value 100, when the mean is 69 and the standard deviation is 5.

(Multiple Choice)

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Question 154

The distribution of scores on a test is mound-shaped and symmetric with a mean score of 78. If 68% of the scores fall between 72 and 84, which of the following is most likely to be the standard deviation of the distribution?

(Multiple Choice)

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Question 155

A recent survey was conducted to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a 3-bedroom house using gas or electric energy had a mean of $142.00 and a standard deviation of $15.00. Assuming the distribution is mound-shaped and symmetric, would you expect to see a 3-bedroom house using gas or electric energy with a monthly utility bill of $239.50? Explain.

(Essay)

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Question 156

Class relative frequencies must be used, rather than class frequencies or class percentages, when constructing a Pareto diagram.

(True/False)

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Question 157

A study was designed to investigate the effects of two variables - (1) a student's level of mathematical anxiety and (2) teaching method - on a student's achievement in a mathematics course. Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 260 with a standard deviation of 30 on a standardized test. Assuming a mound-shaped and symmetric distribution, what percentage of scores exceeded 200?

(Multiple Choice)

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Question 158

A survey was conducted to determine how people feel about the quality of programming available on television. Respondents were asked to rate the overall quality from 0 (no quality at all) to 100 (extremely good quality). The stem-and-leaf display of the data is shown below. Stem Leaf 3 3 6 4 0 3 4 7 8 9 9 9 5 0 1 1 2 3 4 5 6 1 2 5 6 6 7 5 8 8 9 3 What percentage of the respondents rated overall television quality as very good (regarded as ratings of 80 and above)?

(Multiple Choice)

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Question 159

An annual survey sent to retail store managers contained the question "Did your store suffer any losses due to employee theft?" The responses are summarized in the table for two years. Compare the responses for the two years using side-by-side bar charts. What inferences can be made from the charts? Employee Theft Percentage in year 1 Percentage in year 2 Yes 34 23 No 51 68 Don't know 15 9 Totals 100 100

(Essay)

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Question 160

Your teacher announces that the scores on a test have a mean of 83 points with a standard deviation of 4 points, so it is reasonable to expect that you scored at least 70 on the test.

In general, the sample mean is a better estimator of the population mean for larger sample sizes.

A shoe company reports the mode for the shoe sizes of men's shoes is 12. Interpret this result.

Chebyshev's rule applies to large data sets, while the empirical rule applies to small data sets.

The sample variance and standard deviation can be calculated using only the sum of the data, $\sum { x }$ , and the sample size, n.

Summary information is given for the weights (in pounds) of 1000 randomly sampled tractor trailers. MIN: 4015 25\%: 5615 MAX: 10,615 75\%: 8615 AVE: 7015 Std. Dev.: 1400 Find the percentage of tractor trailers with weights between 5615 and 8615 pounds.

The z-score for a value x is -2.5. State whether the value of x lies above or below the mean and by how many standard deviations.

The top speeds for a sample of five new automobiles are listed below. Calculate the standard deviation of the speeds. Round to four decimal places. 180, 100, 195, 130, 155

Which expression represents the sum of the squares of the observations in a data set? A) $\sum x ^ { 2 }$ B) $\left( \sum x ^ { 2 } \right) ^ { 2 }$ C) $\sum { \sqrt { x } }$ D) $\sqrt { \sum { x } }$

What class percentage corresponds to a class relative frequency of .37?

Find the z-score for the value 100, when the mean is 69 and the standard deviation is 5.

The distribution of scores on a test is mound-shaped and symmetric with a mean score of 78. If 68% of the scores fall between 72 and 84, which of the following is most likely to be the standard deviation of the distribution?

Class relative frequencies must be used, rather than class frequencies or class percentages, when constructing a Pareto diagram.

Statistics, Data, and Statistical Thinking

Probability

Discrete Random Variables

Continuous Random Variables

Sampling Distributions

Inferences Based on a Single Sample: Estimation With Confidence Intervals

Inferences Based on a Single Sample: Tests of Hypothesis

Inferences Based on a Two Samples: Confidence Intervals and Tests of Hypotheses

Analysis of Variance: Comparing More Than Two Means

Simple Linear Regression

Multiple Regression and Model Building

Categorical Data Analysis

Nonparametric Statistics

Filters

Exam 2: Methods for Describing Sets of Data

Your teacher announces that the scores on a test have a mean of 83 points with a standard deviation of 4 points, so it is reasonable to expect that you scored at least 70 on the test.

In general, the sample mean is a better estimator of the population mean for larger sample sizes.

A shoe company reports the mode for the shoe sizes of men's shoes is 12. Interpret this result.

Chebyshev's rule applies to large data sets, while the empirical rule applies to small data sets.

The sample variance and standard deviation can be calculated using only the sum of the data, ∑x\sum { x }∑x , and the sample size, n.

Summary information is given for the weights (in pounds) of 1000 randomly sampled tractor trailers. MIN: 4015 25\%: 5615 MAX: 10,615 75\%: 8615 AVE: 7015 Std. Dev.: 1400 Find the percentage of tractor trailers with weights between 5615 and 8615 pounds.

The z-score for a value x is -2.5. State whether the value of x lies above or below the mean and by how many standard deviations.

The top speeds for a sample of five new automobiles are listed below. Calculate the standard deviation of the speeds. Round to four decimal places. 180, 100, 195, 130, 155

Which expression represents the sum of the squares of the observations in a data set? A) ∑x2\sum x ^ { 2 }∑x2 B) (∑x2)2\left( \sum x ^ { 2 } \right) ^ { 2 }(∑x2)2 C) ∑x\sum { \sqrt { x } }∑x​ D) ∑x\sqrt { \sum { x } }∑x​

What class percentage corresponds to a class relative frequency of .37?

Find the z-score for the value 100, when the mean is 69 and the standard deviation is 5.

The distribution of scores on a test is mound-shaped and symmetric with a mean score of 78. If 68% of the scores fall between 72 and 84, which of the following is most likely to be the standard deviation of the distribution?

Class relative frequencies must be used, rather than class frequencies or class percentages, when constructing a Pareto diagram.

Statistics, Data, and Statistical Thinking

Probability

Discrete Random Variables

Continuous Random Variables

Sampling Distributions

Inferences Based on a Single Sample: Estimation With Confidence Intervals

Inferences Based on a Single Sample: Tests of Hypothesis

Inferences Based on a Two Samples: Confidence Intervals and Tests of Hypotheses

Analysis of Variance: Comparing More Than Two Means

Simple Linear Regression

Multiple Regression and Model Building

Categorical Data Analysis

Nonparametric Statistics

Filters

The sample variance and standard deviation can be calculated using only the sum of the data, $\sum { x }$ , and the sample size, n.

Which expression represents the sum of the squares of the observations in a data set? A) $\sum x ^ { 2 }$ B) $\left( \sum x ^ { 2 } \right) ^ { 2 }$ C) $\sum { \sqrt { x } }$ D) $\sqrt { \sum { x } }$