Exam 2: Methods for Describing Sets of Data

Test scores for a history class had a mean of 79 with a standard deviation of 4.5. Test scores for a physics class had a mean of 69 with a standard deviation of 3.7. One student earned a 59 on the history test and a 98 on the physics test. Calculate the z-score for each test. On which test did the student perform better?

The speeds of the fastballs thrown by major league baseball pitchers were measured by radar gun. The mean speed was 87 miles per hour. The standard deviation of the speeds was 5 mph. Which of The following speeds would be classified as an outlier?

Fill in the blank. __________ gives us a method of interpreting the standard deviation of any data set, regardless of the shape of the distribution.

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 a summary of recent real estate sales, the median home price is given as $325,000. What percentile corresponds to a home price of $325,000?

The range is an insensitive measure of data variation for large data sets because two data sets can have the same range but be vastly different with respect to data variation.

The amount spent on textbooks for the fall term was recorded for a sample of five hundred university students. The mean expenditure was calculated to be $500 and the median expenditure Was calculated to be $425. Which of the following interpretations of the median is correct?

Box plots are used to detect outliers in qualitative data sets, while z-scores are used to detect outliers in quantitative data sets.

Explain how using a scale break on the vertical axis of a histogram can be misleading.

According to the empirical rule, z-scores of less than -3 or greater than 3 occur very infrequently for data from a mounded and symmetric distribution

A dot plot of the speeds of a sample of 50 cars passing a policeman with a radar gun is shown below. What proportion of the motorists were driving above the posted speed limit of 55 miles per hour?

The amount of television viewed by todayʹs youth is of primary concern to Parents Against Watching Television (PAWT). 300 parents of elementary school-aged children were asked to Estimate the number of hours per week that their child watches television. The mean and the Standard deviation for their responses were 19 and 2, respectively. PAWT constructed a Stem-and-leaf display for the data that showed that the distribution of times was a symmetric, Mound-shaped distribution. Give an interval where you believe approximately 95% of the Television viewing times fell in the distribution.

The amount spent on textbooks for the fall term was recorded for a sample of five hundred university students. The mean expenditure was calculated to be $500 and the standard deviation of The expenditures was calculated to be $100. Suppose a randomly selected student reported that Their textbook expenditure was $700. Calculate the z-score for this studentʹs textbook expenditure.

Which is expressed in the same units as the original data, the variance or the standard deviation?

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 84 And 4, respectively, and the distribution of scores is mound-shaped and symmetric. What Percentage of test-takers scored better than a trainee who scored 72?

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. 195, 135, 200, 190, 150

The amount of television viewed by todayʹs youth is of primary concern to Parents Against Watching Television (PAWT). Three hundred parents of elementary school-aged children were asked to estimate the number of hours per week that their child watches television. The upper quartile for the distribution was given as 17 hours. Interpret this value.

The table shows the number of each type of car sold in June. Car Number compact 7,204 sedan 9,089 small SUV 20,418 large SUV 13,691 minivan 15,837 truck 15,350 Total 81,589 a. Construct a relative frequency table for the car sales. b. Construct a Pareto diagram for the car sales using the class percentages as the heights of the bars.

A shoe retailer keeps track of all types of information about sales of newly released shoe styles. One newly released style was marketed to tall people. Listed below are the shoe sizes of 12 Randomly selected customers who purchased the new style. Find the mode of the shoe sizes. 9 11 12 11 8 10 8 11 10 11 9 10

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 28.12 26.94 MEDIAN 27.11 25.51 Interpret the year 5 median dropout rate of 25.51.