Lab 13 - Hypothesis Testing Here is the scenario laid out for lab week 13:

Imagine that a census report has recently come out indicating that in the past 30 days -- the population average of poor mental health days was 3.56 with a population standard deviation of 6.9. Now imagine that at your government agency, you suspect this is far worse. You think that the number of days of poor mental health in the past 30 days will be much higher. How can we test this? We decide to survey 300 of our coworkers and ask them to indicate how many days of the last 30 were poor mental health days. Our resource is an Excel spreadsheet called InClassPractice t-tests. It contains our survey results. Your mission: Test the hypothesis outlined in the scenario above and report your results. The eight steps of hypothesis testing are included as a reminder below. Use lab13 quiz/survey to report your work. 8 steps of Hypothesis Testing

1. State a null hypothesis

2. State an alternative hypothesis

3. Make a decision rule. This involves deciding the maximum probability of making a type I error you are willing to accept (level of statistical significance). This level of statistical significance is represented by and called the "alpha" level.

4. Determine whether you are conducting a "one-tailed" or "two-tailed" test of statistical significance.

5. Choose an appropriate test statistic and sampling distribution. Depends on the type of population parameter you are estimating and the size of your sample.

6. Determine the critical value of the test statistic. The critical value is the value of the test statistic that must be obtained in order to reject the null hypothesis at the specified alpha level.

7. Calculate the sample statistic or estimator of the population parameter.

8. Calculate the observed value of the test statistic.

9. Compare the observed value of the test statistic to the critical value of the test statistic.

DECISION TIME: The decision to reject or not reject the null hypothesis depends on the comparison between the observed test statistic and the critical value.