Answer
The three assumptions needed for a confidence interval are that the data is an SRS, the population is approximately normal, and the standard deviation of the population is known.
The most important concern is whether the data is an SRS, as that determines whether the results are meaningful at all.
The normality of the population is a smaller concern because the sampling distribution will be approximately normal. The standard deviation is given in the problem, so we won't worry about that.
Work Step by Step
The three assumptions needed for a confidence interval are that the data is an SRS, the population is approximately normal, and the standard deviation of the population is known.
The most important concern is whether the data is an SRS, as that determines whether the results are meaningful at all.
The normality of the population is a smaller concern because the sampling distribution will be approximately normal. The standard deviation is given in the problem, so we won't worry about that.
