Question

The mayor is interested in finding a 95% confidence interval for the mean number of pounds of trash per person per week that is generated in the city. The study included 225 residents whose mean number of pounds of trash generated per person per week was 37.5 pounds and the standard deviation was 6.6 pounds. Round answers to 3 decimal places where possible.

a. To compute the confidence interval use a t or z  distribution?

b. With 95% confidence the population mean number of pounds per person per week is between ___________ and ___________ pounds.

c. If many groups of 225 randomly selected members are studied, then a different confidence interval would be produced from each group. About ____________ percent of these confidence intervals will contain the true population mean number of pounds of trash generated per person per week and about ____________ percent will not contain the true population mean number of pounds of trash generated per person per week.

Answer 1

c.

If many groups of 225 randomly selected members are studied, then a different confidence interval would be produced from each group. About _95%_ percent of these confidence intervals will contain the true population mean number of pounds of trash generated per person per week and about _5%_ percent will not contain the true population mean number of pounds of trash generated per person per week.