# Normal Distribution

Question

Use the normal distribution to approximate the desired probability.
A coin is tossed 20 times. A person, who claims to have extrasensory perception, is asked to predict the outcome of each flip in advance. She predicts correctly on 14 tosses. What is the probability of being correct 14 or more times by guessing? Does this probability seem to verify her claim? (Points : 5)

0.4418, no

0.0582, no

0.4418, yes

0.0582, yes

Question

Solve the problem.
The following confidence interval is obtained for a population proportion, p: 0.689 < p < 0.723. Use these confidence interval limits to find the margin of error, E. (Points : 5)

0.017

0.706

0.018

0.034

Question

Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places.

95% confidence; n = 320, x = 60 (Points : 5)

0.0449

0.0514

0.0428

0.0385

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