For degree of freedom can you put in part B and not part D please !

Espanol It seems these days that college graduates who are employed full-time work more than 40-hour weeks. Data are available that can help us decide if this is true. A survey was recently sent to a group of adults selected at random. There were 19 respondents who were college graduates employed full-time. The mean number of hours worked per week by these 19 respondents was 45 hours, with a standard deviation of 9 hours. Assume that the population of hours worked per week by college graduates employed full-time is normally distributed with mean J. Can we conclude that | is greater than 40 hours? Use the 0.05 level of significance. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.) (a) State the null hypothesis lin and the alternative hypothesis H a P H :0 (b) Determine the type of test statistic to use. Degrees of freedom: 0-0 050 020 (c) Find the value of the test statistic. (Round to three or more decimal places.) 0+0 00 X 5 2 (d) Find the critical value. (Round to three or more decimal places.) (e) Can we conclude, at the 0.05 level of significance, that the mean number of hours worked per week by college graduates is greater than 40 hours? OYes ONo