1) The monthly incomes for a group of engineers are: $2,200, $2,400, $2,600, $3,100, $3,400, and $3,700. What are these ungrouped numbers called?

A. Class limits
B. Raw data
C. Histograms
D. Class frequencies

2) What happens as the number of classes in a histogram decreases?

A. Class interval width increases.
B. Class intervals become rounder.
C. Central tendency becomes more obvious.
D. We get better resolution of the data

3) What is the term for a number of observations in a class in a frequency distribution?

A. Class interval
B. Class array
C. Class midpoint
D. Class frequency

4) What is the slope of the line: 2y + 8x = 26

A. 8
B. 2
C. -4
D. 1/4

5) What is the slope of the line: 5y â?" x = 10

A. 2
B. -1
C. 1/2
D. 1/5

6) What is the slope of the line: 36x â?" 9y = 15

A. 36
B. 3
C. -5/3
D. 4

7) Which statement is true of the y-intercept in the linear regression model?

A. It is always a positive value.
B. The value depends on the slope of the line.
C. It may be any value.
D. It is always zero.

8) A linear regression model has a slope of â?"2.5 and an intercept of 10. The sample coefficient of determination is 0.50. What is the value of the sample correlation coefficient?

A. -0.71
B. 0.71
C. -0.25
D. 0.25

9) Which of the following is observed in a scatter plot when there is an inverse relationship between x and y?

A. Points are mostly in the lower left and upper right quadrants.
B. Points curve up as it moves to the right.
C. Points slope down as it moves to the right.
D. Points create a horizontal line.