A grouped frequency distribution has a mean of 200 and a standard deviation of 20. The class limits for one class are 220 up to 240. What are the standard normal z-statistics for the class limits?
A) -20 and 20.
B) -2.0 and -1.0
C) 200 and 220
D) 1.0 and 2.0

Question

Quizplus · Accepted Answer

The z-statistic is calculated as (X - mean) / standard deviation. For 220: (220-200)/20 = 1.0, and for 240: (240-200)/20 = 2.0.

A Grouped Frequency Distribution Has a Mean of 200 and a Standard