Question

The average American gets a haircut every 39 days. Is the average smaller for college students? The data below shows the results of a survey of 13 college students asking them how many days elapse between haircuts. Assume that the distribution of the population is normal.

30, 40, 37, 27, 45, 39, 43, 34, 35, 41, 43, 34, 27

What can be concluded at the the αα = 0.05 level of significance level of significance?

1. For this study, we should use Select an answer t-test for a population mean z-test for a population mean
2. The null and alternative hypotheses would be:

H0:H0:  ? p μ  Select an answer = ≤ < > ≠ ≥       

H1:H1:  ? μ p  Select an answer = ≤ ≠ < ≥ >    

3. The test statistic ? t z  =  (please show your answer to 3 decimal places.)
4. The p-value =  (Please show your answer to 3 decimal places.)
5. The p-value is ? ≤ >  αα
6. Based on this, we should Select an answer reject accept fail to reject  the null hypothesis.
7. Thus, the final conclusion is that ...
   • The data suggest the populaton mean is significantly lower than 39 at αα = 0.05, so there is enough evidence to conclude that the population mean number of days between haircuts for college students is lower than 39.
   • The data suggest the population mean number of days between haircuts for college students is not significantly lower than 39 at αα = 0.05, so there is not enough evidence to conclude that the population mean number of days between haircuts for college students is lower than 39.
   • The data suggest the population mean is not significantly lower than 39 at αα = 0.05, so there is enough evidence to conclude that the population mean number of days between haircuts for college students is equal to 39.

Answer 1