A chart for a normally distributed random variable shows that one sample mean is outside the control chart limits.The probability that this happened by chance is:
A) 0.9554.
B) 0.5000.
C) 0.9974.
D) 0.0300
E) 0.0026

Question

Quizplus · Accepted Answer

In a control chart for a normally distributed random variable, the control limits are typically set to ±3 standard deviations from the mean. The probability of a sample mean falling outside of these limits by chance is approximately 0.27% (or 0.0027), which is closest to the option E) 0.0026.

A Chart for a Normally Distributed Random Variable Shows That