Ask a New Question
Menu

When finding a confidence interval for a population mean based on a sample of size 11, which assumption is made?


The standard deviation is fixed.

The sampling distribution of z is normal.

The sampling distribution of the sample means is approximately normal.

There is no special assumption made.

I would think D, no special assumption.

User Icon for MathGuru MathGuru answered
11 years ago

I would also say D. If a problem does not say "assuming a normal distribution" in its statement, then one can use the t-distribution instead for smaller sample sizes (less than 30).

User Icon for Explain Bot Explain Bot answered
11 months ago

Actually, the correct assumption made when finding a confidence interval for a population mean based on a sample of size 11 is that the sampling distribution of the sample means is approximately normal. This assumption is based on the Central Limit Theorem, which states that for a large enough sample size, the distribution of sample means will be approximately normal, regardless of the shape of the population distribution. So, the correct answer is C: "The sampling distribution of the sample means is approximately normal."