7. Thirty prospective teachers take a standards-based teacher competency test. The 7.

results are as follows (each score reflects the percentage of standards for which the prospective teacher demonstrates proficiency):

81 91 89 81 79 82 70 92 80 64 73 86 87 72 74 75 90 85 83 82 79 82 78 96 77 85 83 87 88 80 Because the range of these 30 scores is 96 −64 32, the plausible values of i are 2 or 3.

(a) How did we get these two values of i?

(b) Construct a frequency distribution with i 3 and 63–65 as the lowest interval;

include score limits and exact limits, frequencies, percentages, cumulative frequencies, and cumulative percentages.

(c) Construct a frequency distribution with i 2 and 64–65 as the lowest interval;

include percentages, cumulative frequencies, and cumulative percentages.

(d) Which frequency distribution do you prefer—one based on i 2 or i 3?

Why?