A recent survey asKed how many hours within the average day

A recent survey asKed \"how many hours, within the average day do you watch television?

Sample size: 1324, Mean : 2.9800, SD : 2.6600, S error:0.0731 95% Confidence Limit

Qa Interpret the 95% confidence interval

Qb What do the sample mean and sd suggest about the likely shape of the population distribution ?

Solution

Confidence Interval Estimate for the Mean

Data

Standard Deviation

2.66

Sample Mean

2.98

Sample Size

1324

Confidence Level

95%

Intermediate Calculations

Standard Error of the Mean=se=sd/sqrt(n)=2.66/sqrt(1324)=

0.0731

Z Value

1.9600

Margin of error=me=se*z=

0.1433

Confidence Interval

Interval Lower Limit =mean-me=

2.84

Interval Upper Limit=mean+me=

3.12

Qa Interpret the 95% confidence interval

We are 95% confident that all the people watching TV falls in the interval (2.84, 3.12)

Qb What do the sample mean and sd suggest about the likely shape of the population distribution ?

Since Sd is as large as mean and the variable is time, the shape of the distribution may be positively skewed