Question

the stem - and - leaf display below gives the test scores for the students in prof. sanders 10 a.m. and 11 a.m. economics classes. there were 27 students in the 10 a.m. class and 11 students in the 11 a.m. class. use the display to answer the questions that follow. test scores for prof. sanders economics classes 10 a.m. 11 a.m. 8 3 3 | 4 | 8 9 8 | 5 | 7 9 7 6 5 5 | 6 | 0 1 7 8 9 8 4 | 7 | 7 8 8 7 6 4 1 1 | 8 | 6 8 1 | 9 | key: 4|3 → 43; 4|8 → 48 (a) what were the ranges for the two classes? 10 a.m. 11 a.m. (b) which class had the higher median score? 10 a.m. 11 a.m. the medians were the same (c) which class had more scores in the 70s? 10 a.m. 11 a.m. each had the same

Explanation:

Step1: Find range for 10 - a.m. class

Range = max - min. For 10 - a.m. class, min = 43, max = 91. So range = 91 - 43 = 48.

Step2: Find range for 11 - a.m. class

For 11 - a.m. class, min = 48, max = 91. So range = 91 - 48 = 43.

Step3: Find median for 10 - a.m. class

There are 27 students. The median is the 14th - ordered value. Arranging scores in order: 43,43,48,58,59,65,65,66,67,69,74,78,78,81,81,84,86,87,91. Median is 74.

Step4: Find median for 11 - a.m. class

There are 11 students. The median is the 6th - ordered value. Arranging scores in order: 48,57,60,61,67,68,77,78,78,80,88. Median is 68.

Step5: Count scores in 70s for 10 - a.m. class

Scores in 70s for 10 - a.m. class are 74,78,78, so 3 scores.

Step6: Count scores in 70s for 11 - a.m. class

Scores in 70s for 11 - a.m. class are 77,78,78, so 3 scores.

Answer:

(a) 10 a.m.: 48, 11 a.m.: 43
(b) 10 a.m.
(c) Each had the same