The probability that a sample mean is within±1 Z of the population mean is about________.
A) 0.34.
B) 0.68.
C) 0.95.
D) 0.99.

Question

Quizplus · Accepted Answer

The probability that a sample mean is within ±1 Z of the population mean is about 0.68, which corresponds to the area under the standard normal curve between -1 and 1 standard deviations from the mean. This is known as the 68-95-99.7 rule, which states that approximately 68% of the values in a normal distribution fall within one standard deviation of the mean, about 95% fall within two standard deviations, and about 99.7% fall within three standard deviations.

The Probability That a Sample Mean Is Within±1 Z of the Population