Stat 217 – HW 4

For all problems, be sure to show your work/explain your calculations/include graphs/include screen captures of applet output.

1) Complete the “mid-quarter feedback” survey in Blackboard under Assignments > Surveys - 3 pts

This is a “survey” in blackboard so your name will not be attached to your answers but I will be able to see whether you submitted the survey.

2) Activity 12-14 (p. 250) – 8 pts

Hints: Make sure you include shaded and scaled and well-labeled sketches. Make sure you fully justify your answers. If you use the table, say how. If you use the applet, include output. In (c), remember you can use the table/applet “in reverse” – “input” the probability and solve for the “X value,” the height that has that probability to the right or left.

3) Activity 13-14 (p. 271-2) – 14 pts

Hints: In (b), it’s asking you to make a sketch like on p. 260 to represent the sampling distribution of sample proportions for this sample size and population and to specify the numerical values of the mean and the standard deviation in this particular context. Make sure you appropriately label your sketch.

4) Continuing the previous problem – 10 pts

(h) Repeat (b) and (f) assuming a sample size of n=800 instead (still assuming one-third of all American households own a pet cat).

(i) Using the Normal Probability Model to determine the probability of obtaining a sample proportion of at most .316 ( < .316) when n = 800.

(j) Provide a careful (long-run relative frequency) interpretation of the probability you found in (i).

(k) Using trial and error, find a value of the sample proportion for which you would be surprised to obtain that value with a random sample of 800 from this population. Hint: Find a value of so that the probability below that value is less than .05.