Identify the distribution (normal, Student t, chi-square) that should be used in each of the following situations. If none of the three distributions can be used, what other method could be used?

a. In constructing a confidence interval of μ, you have 75 sample values and they appear to be from a population with a skewed distribution. The population standard deviation is not known.

b. In constructing a confidence interval estimate of σ, you have 75 sample values and they appear to be from a population with a skewed distribution.

c. In constructing a confidence interval estimate of σ, you have 75 sample values and they appear to be from a population with a normal distribution.

d. In constructing a confidence interval estimate of p, you have 1200 survey respondents and 5% of them answered “yes” to the first question.

e. In constructing a confidence interval estimate of p, you have 20 survey respondents and 5% of them answered “yes” to the first question.