Just (un)lucky? One of the students in the introductory Statistics class in Exercise 7 claims to have tossed her coin 200 times and found only 42% heads. What do you think of this claim? Explain.

Exercise 7

More coins. Suppose the class in Exercise 5 repeats the coin-tossing experiment.

a) The students toss the coins 25 times each. Use the 68-95-99.7 Rule to describe the sampling distribution model.

b) Confirm that you can use a Normal model here.

c) They increase the number of tosses to 64 each. Draw and label the appropriate sampling distribution model. Check the appropriate conditions to justify your model.

d) Explain how the sampling distribution model changes as the number of tosses increases.

Exercise 5

Coin tosses. In a large class of introductory Statistics students, the professor has each person toss a coin 16 times and calculate the proportion of his or her tosses that were heads. The students then report their results, and the professor plots a histogram of these several proportions.

a) What shape would you expect this histogram to be? Why?

b) Where do you expect the histogram to be centered?

c) How much variability would you expect among these proportions?

d) Explain why a Normal model should not be used here.