Statistics Unit Review

The stem-and-leaf diagram below gives the distribution of the ages in years of 20 participants at a family reunion. Which of the following statements about the distribution is correct?

• The first quartile is larger than the third quartile.

• The distribution is strongly skewed to the left.

• It makes the most sense to use the mean and standard deviation as a numerical summary of the center and spread of this distribution.

• The mean is larger than the median.

• A

• B

• C

• D

• E

• A

• B

• C

• D

• E

Some descriptive statistics for a set of test scores are shown above. For this test, a certain student has a standardized score of z = -1.2. What score did this student receive on the test?

• 266.28

• 779.42

• 1008.02

• 1083.38

• 1311.98

What is the branch of mathematics dealing with the collection, analysis, interpretation, presentation, and organization of data?

• Statistics

• Algebra

• Geometry

• Calculus

What is the branch of science and mathematics that deals with the collection, organization, or presentation, interpretation, and analysis of data regardless of discipline?

What is the word in statistics for any characteristic or attribute of a person, place, or thing?

• variable

• descriptive statistic

• inferential statistic

• parameter

Data were collected on the amount, in dollars, that individual customers spent on dinner in an Italian restaurant. The quartiles for these data are given in the picture. Which of the following statements must be true for these customers?

• At least half of the customers spent less than or equal to $44.27 and at least half spent greater than or equal to $44.27.

• Seventy-five percent of the customers spent between $36.27 and $58.97.

• Twenty-five percent of the customers spent less than or equal to $58.97 and the remaining 75 percent spent greater than or equal to $58.97.

• The mean amount spent by customers is $44.27.

• A majority of customers spent $44.27.

The back-to-back stem-and-leaf plot below gives the percentage of students who dropped out of school at each of the 49 high schools in a large metropolitan school district. Which of the following statements is NOT justified by these data?

• The drop-out rate decreased in each of the 49 schools between the 1989-90 and 1992-1993 school years.

• For the school years shown, most students in the 49 schools did not drop out of high school.

• In general drop-out rates decreased between the 1989-90 and 1992-1993 school years.

• The median drop-out rate of the 49 high schools decreased between the 1989-90 and 1992-1993 school years.

• The spread between the schools with the lowest drop-out rates and those with the highest drop-out rates did not change much between the 1989-90 and 1992-1993 school years.

Which of the following is the best estimate of the standard deviation of the distribution shown in the figure above?

• 5

• 10

• 30

• 50

• 60