Exam 2: Methods for Describing Sets of Data

The amount of time workers spend commuting to their jobs each day in a large metropolitan city has a mean of 70 minutes and a standard deviation of 20 minutes. Assuming nothing is known About the shape of the distribution of commuting times, what percentage of these commuting Times are between 30 and 110 minutes?

The box plot shown below displays the amount of soda that was poured by a filling machine into 12-ounce soda cans at a local bottling company. Based on the box plot, what shape do you believe the distribution of the data to have?

In symmetric distributions, the mean and the median will be approximately equal.

The test scores of 30 students are listed below. Which number could be the 30th percentile? 31 41 45 48 52 55 56 56 63 65 67 67 69 70 70 74 75 78 79 79 80 81 83 85 85 87 90 92 95 99

A larger standard deviation means greater variability in the data.

What number is missing from the table? Grades on Test Frequency Relative Frequency A 6 .24 B 7 C 9 .36 D 2 .08 F 1 .04

A sociologist recently conducted a survey of citizens over 60 years of age who have net worths too high to qualify for Medicaid but have no private health insurance. The ages of the 25 uninsured Senior citizens were as follows: 68 73 66 76 86 74 61 89 65 90 69 92 76 62 81 63 68 81 70 73 60 87 75 64 82 Find the upper quartile of the data.

The ages of five randomly chosen professors are 47, 55, 52, 63, and 66. Calculate the sample variance of these ages.

The data below represent the numbers of absences and the final grades of 15 randomly selected students from a statistics class. Construct a scattergram for the data. Do you detect a trend? Student Number of Absences Final Grade as a Percent 1 5 79 2 6 78 3 2 86 4 12 56 5 9 75 6 5 90 7 8 78 8 15 48 9 0 92 10 1 78 11 9 81 12 3 86 13 10 75 14 3 89 15 11 65

The scores of nine members of a womenʹs golf team in two rounds of tournament play are listed below. Player 1 2 3 4 5 6 7 8 9 Round 1 85 90 87 78 92 85 79 93 86 Round 2 90 87 85 84 86 78 77 91 82 Construct a scattergram for the data.

Calculate the range of the following data set: 8, 7, 9, 1, 6, 10, 4, 7, 4

At the U.S. Open Tennis Championship a statistician keeps track of every serve that a player hits during the tournament. The statistician reported that the mean serve speed was 100 miles per hour (mph)and the standard deviation of the serve speeds was 15 mph. Assume that the statistician Also gave us the information that the distribution of serve speeds was mound-shaped and Symmetric. What percentage of the playerʹs serves were between 115 mph and 145 mph?

If 25% of your statistics class is sophomores, then in a pie chart representing classifications of the students in your statistics class the slice assigned to sophomores is 90°.

Use a graphing calculator or software to construct a box plot for the following data set. 12 18 14 17 19 16 14 18 15 17 11 13 14 11 16 18 15 13 17 15 14 19 12 16 17

By law, a box of cereal labeled as containing 32 ounces must contain at least 32 ounces of cereal. The machine filling the boxes produces a distribution of fill weights that is mound-shaped and symmetric, with a mean equal to the setting on the machine and with a standard deviation equal to 0.04 ounce. To ensure that most of the boxes contain at least 32 ounces, the machine is set so that the mean fill per box is 32.12 ounces. What percentage of the boxes do, in fact, contain at least 32 ounces?

The amount spent on textbooks for the fall term was recorded for a sample of five university students - $400, $350, $600, $525, and $450. Calculate the value of the sample median for the data.

The output below displays the mean and median for the state high school dropout rates in year 1 and in year 5. Year 1 Year 5 N 51 51 MEAN 28.97 26.36 MEDIAN 27.42 25.25 Use the information to determine the shape of the distributions of the high school dropout rates in year 1 and year 5.

Either vertical or horizontal bars can be used when constructing a bar graph.

Calculate the standard deviation of a sample for which $n = 6 , \sum x ^ { 2 } = 830 , \sum x = 60$

The amount spent on textbooks for the fall term was recorded for a sample of five university students - $400, $350, $600, $525, and $450. Calculate the value of the sample range for the data.