Suppose a 90% confidence interval for μ turns out to be (1000, 2100). If this interval was based on a sample ofsize n = 25, explain what assumptions are necessary for this interval to be valid.
A) The population must have an approximately normal distribution.
B) The sampling distribution of the sample mean must have a normal distribution.
C) The population of salaries must have an approximate t distribution.
D) The sampling distribution must be biased with 24 degrees of freedom.

Question

Quizplus · Accepted Answer

The assumption necessary for the confidence interval to be valid is that the population from which the sample is drawn must have an approximately normal distribution, especially since the sample size is small (n = 25).

Suppose a 90% Confidence Interval for μ Turns Out to Be