At this point in the text (and at two later points) there is a set of problems titled What would you recommend? These problems help you review and integrate your knowledge. You are to choose an appropriate statistic from among those you learned in the first five chapters. For each problem that follows, recommend a statistic that answers the question and note why you recommend that statistic.
a. Registration figures for the American Kennel Club show which dog breeds are common and which are uncommon. For a frequency distribution for all breeds, what central tendency statistic is appropriate?
b. Among a group of friends, one person is the best golfer. Another person in the group is the best at bowling. What statistical technique allows you to determine that one of the two is better than the other?
c. Tuition at Almamater U. has gone up each of the past 5 years. How can I predict what it will be in 25 years when my child enrolls?
d. Each of the American states has a certain number of miles of ocean coastline (ranging from 0 to 6640 miles). Consider a frequency distribution of these 50 scores. What central tendency statistic is appropriate for this distribution? Explain your choice. What measure of variability do you recommend?
e. Jobs such as “appraiser” require judgments about the value of a unique item. Later a sale price establishes an actual value. Suppose two applicants for an appraiser’s job made judgments about 30 items. After the items sold, an analysis revealed that when each applicant’s errors were listed, the average was zero. What other analysis of the data might provide an objective way to decide that one of the two applicants was better?
f. Suppose you study some new, relatively meaningless material until you know it all. If you are tested 40 minutes later, you recall 85 percent; 4 hours later, 70 percent; 4 days later, 55 percent; and 4 weeks later, 40 percent. How can you express the relationship between time and memory?
g. A table shows the ages and the number of voters in the year 2006. The age categories start with “18–20” and end with “65 and over.” What statistic can be calculated to best describe the age of the typical voter?
h. For a class of 40 students, the study time for the first test ranged from 30 minutes to 6 hours. The grades ranged from a low of 48 to a high of 98. What statistic describes how the variable Study time is related to the variable Grade?