Exam 3: Describing, Exploring, and Comparing Data

A student earned grades of 84, 78, 84, and 72 on her four regular tests. She earned a grade of_ 78 on the final exam and 86 on her class projects. Her combined homework grade was 87. The Four regular tests count for 40% of the course grade, the final exam counts for 30%, the project Counts for 10%, and homework counts for 20%. What is her weighted mean grade? Round to One decimal place.

The customer service department of a phone company is experimenting with two different systems. On Monday they try the first system which is based on an automated menu system. On Tuesday they try the second system in which each caller is immediately connected with a Live agent. A quality control manager selects a sample of seven calls each day. He records the Time for each customer to have his or her question answered. The times (in minutes)are listed below. Find the coefficient of variation for each of the two sets of data, then compare the Variation. Round results to one decimal place. Automated Menu: $11.7 \quad 7.4 \quad 3.9 \quad 2.9 \quad 9.2 \quad 6.3 \quad 5.5$ Live agent: 6.2 2.9 4.4 4.1 3.4 5.2 3.7

Listed below are the systolic blood pressures (in mm Hg)for a sample of men aged 20-29 years and for a sample of men aged 60-69 years. Men aged 20-29: 117 122 129 118 131 123 Men aged 60-69: 130 153 141 125 164 139 Find the coefficient of variation for each of the two sets of data, then compare the variation. Round results to one decimal place.

When finding percentiles, if the locator L is not a whole number, one procedure is to interpolate so that a locator of 23.75, for example, leads to a value that is 3/4 of the way Between the 23rd and 24th scores. Use this method of interpolation to find P75 for the set of Test scores below. 51 54 64 68 72 74 76 83 94 94 99

Describe any similarities or differences in the two distributions represented by the following boxplots. Assume the two boxplots have the same scale.

A male student of the author has a measured pulse rate of 52 beats per minute. According to a National Center for Health Statistics data set, males have a mean pulse rate of 67.3 beats per minute and a standard deviation of 10.3 beats per minute. Determine whether the student's pulse rate is significantly low or high by determining the difference between the student's pulse rate and the mean pulse rate of males and how many standard deviations that difference represents by calculating the z score. Consider usual pulse rates to be within 2 standard deviations of the mean.

The test scores of 40 students are listed below. Find P56._ 30 35 43 44 47 48 54 55 56 57 59 62 63 65 66 68 69 69 71 72 30 35 43 44 47 48 54 55 56 57 59 62 63 65 66 68 69 69 71 72 72 73 74 76 77 77 78 79 80 81 81 82 83 85 89 92 93 94 97 98 72 73 74 76 77 77 78 79 80 81 81 82 83 85 89 92 93 94 97 98

Construct a data set for which the range is misleading as a measure of variation. the range is misleading and suggest an alternative measure of variation.

A company had 80 employees whose salaries are summarized in the frequency distribution below. Find the standard deviation. Salary (dollars) Employees 5,001-10,000 19 10,001-15,000 14 15,001-20,000 12 20,001-25,000 16 25,001-30,000 19

The following are interval times (minutes)between eruptions of the Old Faithful geyser in Yellowstone National Park (based on U.S. National Park Service data). 81 81 86 87 89 92 93 94 95 96 97 98 98 101 101 106 Identify the five number summary and construct a boxplot of these data.

Last year, nine employees of an electronics company retired. Their ages (in years)at_ retirement are listed below. Find the mode(s)for the given sample data. 51 61 62 57 50 67 68 58 53

How will a high outlier in a data set affect the mean and median?

A comparison is made between summer electric bills of those who have central air and those who have window units. Find the mean and median for each of the two samples, then compare the two sets of results. May June July Aug Sept Central \ 32 \ 64 \ 80 \ 90 \ 65 Window \ 15 \ 84 \ 99 \ 120 \ 40

Scores on a test have a mean of 66 and a standard deviation of 9. Michelle has a score of 57._ Convert Michelle's score to a z score.

Which do you think has less variation: the IQ scores of students in your statistics class or the IQ scores of a simple random sample taken from the general population? Why?

Find the variance for the given data. Round your answer to one more decimal place than the_ original data. To get the best deal on a microwave oven, Jeremy called six appliance stores And asked the cost of a specific model. The prices he was quoted are listed below: \ 663 \ 273 \ 410 \ 622 \ 174 \ 374

Explain how two data sets could have equal means and modes but still differ greatly. Give an example with two data sets to illustrate.

Construct a boxplot for the given data. Include values of the 5-number summary in all_ boxplots. The test scores of 40 students are listed below. 25 35 43 44 47 48 54 55 56 57 59 62 63 65 66 68 69 69 71 72 72 73 74 76 77 77 78 79 80 81 81 82 83 85 89 92 93 94 97 98

If your score on your next statistics test is converted to a z score, which of these z scores would you prefer?

The local Tupperware dealers earned these commissions last month: \ 2894.21 \ 1777.15 \ 2144.77 \ 4096.37 \ 4046.29 \ 1786.37 \ 3296.69 \ 4086.27 \ 2784.22 \ 4027.79 What was the mean commission earned? Round your answer to the nearest cent.