Show your R work (both your input and your output) for each question below. You may find Section 22.1 in the reading useful.

## Mean and Standard Deviation

Suppose you have the following data:

7, 9, 4, 12, 15, 13

- Compute the mean (write a sentence with your answer).
- Compute the standard deviation (write a sentence with your answer).

## P-value

- Compute the p-value assuming you computed t=5.678, df=13, and H
_{a}is a “greater than”. Show your R code and a graphic. - Make a decision about μ if α=0.01.

## Types of Variability

Describe the difference between natural and sampling variability.