Question

For each of the examples below, go through the four steps of hypothesis testing; report your results in APA format.

1. According to 2014 data from the Centers for Disease Control and Prevention, the average life expectancy in the United States is 78.74 years with other sources listing the standard deviation, σ, for this data as 16.5 years. A researcher is interested in determining if rock musicians die at an earlier age and collects a random sample of 45 dead rock musicians. The researcher finds an average age of death of 45.2 years for the sample. Use this statistic to evaluate the researcher’s hypothesis.

2. Dr. Graham is interested in determining if middle-aged adults use text messaging more or less frequently than the general population. Dr. Graham collects information on text messaging from a random sample of 50 adults ages 25 to 44. Dr. Graham finds that these individuals send or receive an average of 68 text messages per day. Using the population mean (and standard deviation) of 41.5 texts per day (34 texts per day), determine whether adults in this age group use text messaging more than the general public.

Answer 1

We would be looking at the first question here as:

Q1) As we are testing here whether the mean age is less than 78.74 years, therefore this is a lower tailed test. The test statistic here is computed as:

As the test statistic here is too low, therefore, the p-value here is approx 0 and we have sufficient evidence here that the test is significant and we can reject the null hypothesis here.

The conclusion of this test is that we have sufficient evidence that rock musicians die at an earlier age