1. A 95% confidence interval for a population mean is (0.5 feet, 0.9 feet), find the value of the statisticx

for this study, in feet.

2.A 95% confidence interval for a population proportion is (0.38, 0.80), find the margin of error for this confidence interval.

3.In estimating a population mean, a sample of size 56 shows thatx

= 25.5feet ands= 6.3 feet. The sample data do not include any outliers or strong skewness. Find the upper endpoint (in feet) for a 2SD confidence interval for the population mean. Be sure to use the multiplier 2 and not 1.96.

If the confidence interval is (0.25, 0.35), then the lower endpoint is 0.25 and the upper endpoint is 0.35.

4.In estimating a population proportion, a sample of size 275 shows 29 successes. Find the upper endpoint for a 2SD confidence interval for the population proportion. Be sure to use the multiplier 2 and not 1.96.

If the confidence interval is (0.25, 0.35), then the lower endpoint is 0.25 and the upper endpoint is 0.35.