Confidence intervals of the population mean may be created for the cases when the population standard deviation is known or unknown. How are these two cases treated differently?
A) Use the z table when s is unknown; use the t table when s is known.
B) Use the z table when s is known; use the t table when s is unknown.
C) Use the z table when σ is unknown; use the t table when σ is known.
D) Use the z table when σ is known; use the t table when σ is unknown.

Question

Quizplus · Accepted Answer

When the population standard deviation (σ) is known, we use the z-table to calculate the confidence interval for the population mean. However, when the population standard deviation (σ) is unknown, we use the t-table to calculate the confidence interval for the population mean.

Confidence Intervals of the Population Mean May Be Created for the Cases