A classmate has estimated that life expectancy worldwide is probably 72 years. In order to test this, you identify a dataset created by the United Nations that tracks average life expectancy, income, and educational attainment across countries. Open the attached file on  named “Human Development” and identify the life expectancy variable. You will use this data as your sample to test the hypothesis: Average life expectancy worldwide is 72 years old.

Recall the steps to hypothesis testing:

1) Establish a null and alternate hypothesis

2) Choose a decision rule (a level of significance)

3) Find critical regions

4) Draw the sample

5) Calculate the test statistic

6) Make the decision

Let’s establish a null and alternate hypothesis together        H0: μ = 72

HA: μ  ≠ 72

Choose a decision rule (a level of significance)

Let’s set our level of significance at: 0.05

2a. Find critical regions

What is the critical value? (Consider how many tails and which test to use based on sample size)

2c. Draw the sample

Sample Mean = Sample Standard deviation = Standard Error =

2d. Calculate the test statistic

Test statistic =

2e. Make the decision

Do you reject or fail to reject the null hypothesis?

Articulate your findings in written words:

2f. Compute a 95% confidence interval.

Confidence Interval = What does this mean? Articulate this in written words.