An instructor finds the more often students ask for help in office hour visits, the greater the improvement in their performance across the semester. Which of the following correlations BEST reflects this relationship between asking for help and course performance?

A) r = -1.00
B) r = .05
C) r = -.50
D) r = .45

A researcher who analyzes prison records of inmates who committed violent assaults while incarcerated is conducting survey research.

Construct a frequency distribution for the set of data below. Use four classes, beginning with "10 up to 20," then "20 up to 30," then "30 up to 40," and finally "40 up to 50."
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Each of the following annuities involves future values. Compute the missing numbers. Use Tables 23-1A and 23-1B or a calculator.
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Which of the following sets of scores has the greatest variability?

A) 7,10,11,15,19
B) 7,7,8,8,10,11
C) 7,7,7,7,7,7
D) 6,6,7,7,7,7

8⅓% of what amount is $10 accurate to the cent?