The z-statistic is appropriate if
A) the sample is chi-square distributed and the degrees of freedom is small.
B) the population mean is known.
C) the population variance is unknown.
D) the distribution of the characteristic is normal or the sample is very large such that the Central-Limit Theorem is operative.
E) both c and d above.

Question

Quizplus · Accepted Answer

The z-statistic is appropriate when the distribution is normal or the sample size is large enough for the Central Limit Theorem to apply, ensuring the sampling distribution of the mean is approximately normal.

The Z-Statistic Is Appropriate If