If the standard deviation, σ is known the z-distribution values may not be used to determine interval estimates for the population mean when
A)n

Question

If the standard deviation, σ is known the z-distribution values may not be used to determine interval estimates for the population mean when
A)n<30
B)the distribution is not normal
C)the distribution is skewed
D)n is big
E)n is small (<30)and the distribution is not normal

Quizplus · Accepted Answer

When the standard deviation (σ) is known, z-distribution values can be used to determine interval estimates for the population mean under the assumption of a normal distribution or when the sample size is large (n ≥ 30) due to the Central Limit Theorem. However, if the sample size is small (n < 30) and the distribution is not normal, the z-distribution should not be used because the Central Limit Theorem does not apply, and the normality assumption is violated.

If the Standard Deviation, σ Is Known the Z-Distribution Values