Here are solutions to requested problems. I am still posting more solutions. Some of the photos may appear rotated.
#8. Solution
#17 Solution
#25 Solution
#27 - Skip, not on exam
#29 - Skip, not on exam.
#32. To increase power you have to decrease overlap between an error and the actual. There are 2 ways to decrease overlap. Take less of the peak by picking a higher alpha. Make the peak narrower by taking a larger sample size.
#40. Type I error occurs when Ho is true and Ha is false. Type II error occurs when Ho is false but the alternate is true. The only way to make a Type II error is to conclude Ho is true when in actuality it is false. If Ho is false then the unemployment rate is actually decreasing rather than staying the same.
#52.t-distributions look like normal distributions but they are flatter and the tails are wider. As the degrees of freedom increases the peak becomes sharper and the tails become smaller meaning the variance decreases. Therefore statements I and III are true and II is false.
#57. Enter the data as a list in your calculator. Then run the TInterval on your calculator using data. Make sure to specify the confidence level is 0.98. My confidence interval is (14.898,15.752) and I'm fairly confident with that answer, pun intended.
#58. ME = (69.75-67.25)/2 = 1.25 inches. The confidence interval is determined by adding and subtracting the margin of error from the mean so it is equal to half the width of the confidence interval.
#70. Solution
#81. Because the P-value is low, we will be rejecting the null hypothesis so it is not choices C or E.
Ho: Age & retirement are independent. Age & retirement are uniformly distributed. (Either one of these would probably be okay.)
Ha: They are not.
If we reject they null, essentially we are saying they are not independent and they are not uniformly distributed.
#91. Skip.
#95. The slope is 4.537037 and it is multiplied by seed density. (It's the first number in the last line of the table.)
A & D are incorrect because they are just provided a value for average lawn quality but they do not relate it to seed density.
C& E are trying to use slope to predict change but they are using the wrong variable or don't refer to one.
B is the correct choice because it relates change in lawn quality to change in seed density.
#96. Skip. You will not have to do a prediction.
#100. Solution