Question

1

.

Confidence Interval and Sampling Error:

You decide to conduct a poll of students in order to determine the percentage of students (p) who agree with the statement “Hot dogs are one of my

favorite foods”. In your poll, you find that 85 out of 100 students agree.

a)

Compute a 95% confidence interval for p.

b)

You wish to ensure that the margin of error is no larger than 2.5%. How many students should you include in your next poll?

2

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Suppose that you are the manager of a casino and you collect data on one of your roulette tables. You find that among the last 10,000 bets, there were only 350 bets for which a red or black number did not win. On average, you expect the proportion of winning bets for black or red to equal p=18/19.

a) Compute a 95% confidence interval for the proportion of winning black or red bets.

b) Conduct a two-sided hypothesis test (α=0.05) for HO: p=18/19. State the relevant p-value and your decision whether to reject or not reject HO.

c) Compare your results in part (a) and (b). Are they consistent?

Answer 1