Suppose a random sample of79items has been taken from a population and32of the items contain the characteristic of interest.

a.Use this information to calculate a 90% confidence interval to estimate the proportion of the population that has the characteristic of interest.

b.Calculate a 95% confidence interval.

c.Calculate a 99% confidence interval.

d.As the level of confidence changes and the other sample information stays constant, what happens to the confidence interval?

Appendix A Statistical Tables

(Round the intermediate values to 2 decimal places, e.g. 0.25. Round your answers to 2 decimal places, e.g. 0.25.)

a.

enter the lower value of the interval

p

enter the upper value of the interval

b.

enter the lower value of the interval

p

enter the upper value of the interval

c.

enter the lower value of the interval

p

enter the upper value of the interval

d.All other things being constant, as the confidenceincreased, the width of the interval

select an option (decreased or increased).