Question

The amount of television viewed by today's youth is of primary concern to Parents Against Watching Television (PAWT). 300 parents of elementary school-aged children were asked to estimate the number of hours per week that their child watched television. The mean and the standard deviation for their responses were 16 and 4, respectively. PAWT constructed a stem-and-leaf display for the data that showed that the distribution of times was a bell-shaped distribution. Give an interval around the mean where you believe most (approximately 95%) of the television viewing times fell in the distribution.

A) between 12 and 20 hours per week
B) between 8 and 24 hours per weelk
C) between4 and 28 hours per week
D) less than 12 and more than 20 hours per week

Answer 1

B) between 8 and 24 hours per week

Explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean of 16, standard deviation of 4.

Give an interval around the mean where you believe most (approximately 95%) of the television viewing times fell in the distribution.

Within 2 standard deviations of the mean, so:

16 - 4*2 = 16 - 8 = 8 hours per week.

16 + 4*2 = 16 + 8 = 24 hours per week.

This means that the correcgt answer is given by option B.