ExampleIn a simple random sample of 150 households,

the sample mean number of computers was 1.32. Assume a population standard deviation of 0.41.

What is the Z for a 95% confidence interval?Construct and interpret a 95% confidence

interval for the population mean number of personal computers per household.

We are 95% confident that the population mean number of personal computers per household is between 1.254 and 1.386.

ExampleIn a simple random sample of 150 households, the

sample mean number of computers was 1.32. Assume a population standard deviation of 0.41.

How would the confidence interval change if you were to change the confidence level from 95% to 99%?

How would the confidence interval change if the sample size had been 200 instead of 150?

How would the confidence interval change if the standard deviation had been 0.61 instead of 0.41?

ExampleIn a survey of 517 music teachers, 403 said that

the video games Guitar Hero and Rock Band have a positive effect on music education.

Construct and interpret a 99% confidence interval for the percentage of music teachers who believe that these video games have a positive effect.

We are 99% confident that the population percentage of music teachers who believe that Guitar Hero and Rock Band have a positive effect on music education is between 73.2% and 82.6%.