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


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

Types of Variability

Describe the difference between natural and sampling variability.