Amounts spent by a sample of 200 customers at a retail store are summarized in the following relative frequency distribution. (See the Excel Data File.) The median amount will fall in the following class interval ________.
A) 0 up to 10
B) 10 up to 20
C) 20 up to 30
D) 30 up to 40

Question

Amounts spent by a sample of 200 customers at a retail store are summarized in the following relative frequency distribution.  (See the Excel Data File.) The median amount will fall in the following class interval ________.
A) 0 up to 10 
B) 10 up to 20 
C) 20 up to 30 
D) 30 up to 40

Quizplus · Accepted Answer

To find the median, we need to first calculate the cumulative frequency. Starting from the first class interval, we add up all the frequencies until we reach the midpoint of the total sample size (n=200/2=100).

Class Interval           |   Frequency  |   Relative Frequency | Cumulative Frequency
--------------------------------------------------------------------------------------
0 up to 10              |      36      |        0.18          |        36
10 up to 20             |      52      |        0.26          |        88
20 up to 30 (median)    |      55      |        0.275         |      143
30 up to 40             |      33      |        0.165         |      176
40 up to 50             |      11      |        0.055         |      187
50 up to 60             |      13      |        0.065         |      200

The median amount will fall in the class interval of 20 up to 30, which has a cumulative frequency of 143.

Amounts Spent by a Sample of 200 Customers at a Retail