Question

bell gave her students a biology test last week. here are the test scores for each of the eighteen students. test scores 79 78 70 66 77 72 70 81 79 78 84 72 85 78 76 82 80 78 (a) complete the grouped frequency distribution for the data. (note that the class width is 6.) test scores frequency 66 to 71 72 to 77 78 to 83 84 to 89 (b) construct a histogram for the data. frequency 10 9 8 7 6 5 4 3 2 1 0 66 to 71 72 to 77 78 to 83 84 to 89 test scores

Explanation:

Step1: Count scores in 66 - 71

Scores: 66, 70, 70. So count = 3.

Step2: Count scores in 72 - 77

Scores: 72, 72, 77, 76. So count = 4.

Step3: Count scores in 78 - 83

Scores: 78, 78, 78, 78, 79, 79, 80, 81, 82. So count = 9.

Step4: Count scores in 84 - 89

Scores: 84, 85. So count = 2.

For part (b), the histogram bars' heights correspond to these frequencies: 66 - 71 (height 3), 72 - 77 (height 4), 78 - 83 (height 9), 84 - 89 (height 2).

Answer:

(a)

Test scores	Frequency
72 to 77	4
78 to 83	9
84 to 89	2

(b) Histogram with:

• Bar for 66 - 71: height 3
• Bar for 72 - 77: height 4
• Bar for 78 - 83: height 9
• Bar for 84 - 89: height 2