On the first test of the semester, the class average was 72 with a standard deviation of 6. On the
second test, the class average was 65 with a standard deviation of 8. Nathan scored 80 on the first
test and 76 on the second. Compared to the rest of the class, on which test did Nathan do better?
- What is the mean of a set of data where Σ = 20, Σx = 245, and Σ(x – )^2 = 13,600?
Cumulative Review Problems
Which of the following are examples of quantitative data?
a. The number of years each of your teachers has taught
b. Classifying a statistic as quantitative or qualitative
c. The length of time spent by the typical teenager watching television in a month
d. The daily amount of money lost by the airlines in the 15 months after the 9/11 attacks
e. The colors of the rainbow
- Which of the following are discrete and which are continuous ?
a. The weights of a sample of dieters from a weight-loss program
b. The SAT scores for students who have taken the test over the past 10 years
c. The AP Statistics exam scores for the almost 50,000 students who took the exam in 2009
d. The number of square miles in each of the 20 largest states
e. The distance between any two points on the number line - Just exactly what is statistics and what are its two main divisions?
- What are the main differences between the goals of a survey and an experiment ?
- Why do we need to understand the concept of a random variable in order to do inferential statistics?
Solutions to Practice Problems
Multiple-Choice
The correct answer is (a). I is correct since the mean is pulled in the direction of the large maximum
value, 150 (well, large compared to the rest of the numbers in the set). II is not correct because the
mode is y —there are three y s and only two 26s. III is not correct because 150 is an outlier (you