A grouped frequency distribution has a mean of 100 and a standard deviation of 20. The class limits for one class are 50 up to 60. What are the standard normal z-statistics for the class limits?
A) -20 and 20.
B) -2.5 and -2.0
C) 2.0 and 2.5
D) -50 and -40

Question

Quizplus · Accepted Answer

The z-statistic is calculated using the formula z = (X - μ) / σ. For the lower class limit, z = (50 - 100) / 20 = -2.5. For the upper class limit, z = (60 - 100) / 20 = -2.0.

A Grouped Frequency Distribution Has a Mean of 100 and a Standard