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The A. C. Nielsen Company reported in the Nielsen Report on Television that the

ID: 3358000 • Letter: T

Question

The A. C. Nielsen Company reported in the Nielsen Report on Television that the mean weekly television viewing time for children aged 2–6 years is 24.85 hours. Assume that the weekly television viewing times of such children are normally distributed with a standard deviation of 6.23 hours and apply the empirical rule to fill in the blanks. Round Answers to 2 decimal places. X.XX

a. Approximately 68% of all such children watch between  and  hours of TV per week.

b. Approximately 95% of all such children watch between and  hours of TV per week.

c. Approximately 99.7% of all such children watch between  and  hours of TV per week.

Explanation / Answer

Mean is 24.85 and s is 6.23

a) z for 68% confidence is 1, thus lower limit is mean-s*z=24.85-6.23*1 =18.62, upper limit is mean+s*z=24.85+6.23*1 =  31.08

b) z for 95% confidence is 1.96, thus lower limit is mean-s*z=24.85-6.23*1.96=12.6392 and upper limit is mean+s*z=24.85+6.23*1.96=37.0608

c) z for 99.7% confidence is 3, thus lower limit is mean-s*z=24.85-6.23*3=6.16 and upper limit is  mean+s*z=24.85+6.23*3=43.54