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Magazine Problem 47
Describe two ways that graphs can be misleading.
Problem 48
How does a scatter plot indicate that two variables are correlated?
Problem 49
Give an example of two variables with a strong positive correlation and explain why this is so.
Problem 52
Construct a grouped frequency distribution for the following data, showing the length, in miles, of the 25 longest rivers in the United States. Use five classes that have the same width. \(\begin{array}{ccccc}2540 & 2340 & 1980 & 1900 & 1900 \\ 1460 & 1450 & 1420 & 1310 & 1290 \\ 1280 & 1240 & 1040 & 990 & 926 \\ 906 & 886 & 862 & 800 & 774 \\\ 743 & 724 & 692 & 659 & 649\end{array}\)
Problem 52
If a set of test scores has a large range but a small standard deviation, describe what this means about students' performance on the test.
Problem 52
When all points in a scatter plot fall on the regression line, what is the value of the correlation coefficient? Describe what this means.
Problem 53
Use the data \(1,2,3,5,6,7\). Without actually computing the standard deviation, which of the following best approximates the standard deviation? a. 2 b. 6 c. 10 d. 20
Problem 57
Intelligence quotients on the Stanford-Binet intelligence test are normally distributed with a mean of 100 and a standard deviation of 16. Intelligence quotients on the Wechsler intelligence test are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to solve Exercises 57-58. Use \(z\)-scores to determine which person has the higher IQ: an individual who scores 128 on the Stanford-Binet or an individual who scores 127 on the Wechsler.
Problem 58
Intelligence quotients on the Stanford-Binet intelligence test are normally distributed with a mean of 100 and a standard deviation of 16. Intelligence quotients on the Wechsler intelligence test are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to solve Exercises 57-58. Use \(z\)-scores to determine which person has the higher IQ: an individual who scores 150 on the Stanford-Binet or an individual who scores 148 on the Wechsler.
Problem 67
What is the midrange and how is it obtained?
