Question

# A study by Allstate Insurance Co. finds that 82% of teenagers have used cell phones while...

A study by Allstate Insurance Co. finds that 82% of teenagers have used cell phones while driving (The Wall Street Journal, May 5, 2010). Suppose a random sample of 100 teen drivers is taken. [You may find it useful to reference the z table.]

a-1. Calculate the standard error for the sampling distribution of the sample proportion. (Do not round intermediate calculations. Round your answer to 4 decimal places.)

a-2. Is the sampling distribution of the sample proportion approximately normal?

• Yes

• No

b. What is the probability that the sample proportion is less than 0.80? (Round “z” value to 2 decimal places, and final answer to 4 decimal places.)

a)

Sample fraction of person using phones while driving, =Population mean=0.82

Sample size,n=100

Standard error of sampling distribution is given by

b)

Since

We can say that sampling distribution of sample proportion is approximately normal.

c)

Let us find Z for

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