1.The following data represent the pH of rain for a random sample of 12 rain dates in a particular region in the northeast US. A normal probability plot suggests the data could come from a population that is normally distributed. A boxplot indicates there are no outliers.

4.68

5.14

5.08

4.83

4.69

4.67

5.71

4.69

4.91

4.72

4.83

4.65

a.Construct a 90% confidence interval for the true mean pH value of rain in this region.

b.Construct a 90% confidence interval for the true variance in the pH value of rain in this region.

c.Construct a 90% confidence interval for the true standard deviation in the pH value of rain in this region.