Suppose you are dog breeder and you want to use a confidence interval to estimate the true mean fertility levels of purebred cocker spaniels. it is known that the distribution of fertility levels of cocker spaniels is normal. how many measurements must you have in order to be sure the sampling distribution of x¯ {"version":"1.1","math":"\bar{x}"} is normal?

Accepted Solution

According to the Central Limit Theorem the sum or average of at least 30 independent random variables with the same distribution is approximately normal. Therefore the answer is 'at least 30 measurements.'