Question

# We have the survey data on the body mass index (BMI) of 662 young women. The...

We have the survey data on the body mass index (BMI) of 662 young women. The mean BMI in the sample wasx¯¯¯=25.3x¯=25.3. We treated these data as an SRS from a Normally distributed population with standard deviationσ=σ=7.8 .

Give confidence intervals for the true population mean BMI and the margins of error for 90%, 95%, and 99% confidence.

Conf. Level Interval (±±0.01) margins of error (±±0.0001)
90% to
95% to
99% to

a)

i) 90% confidence interval estimate for population mean is,

The 90% confidence interval is, (24.80, 25.80)

ii) 95% confidence interval estimate for population mean is,

The 95% confidence interval is, (24.71, 25.89)

iii) 99% confidence interval estimate for population mean is,

The 99% confidence interval is, (24.52, 26.08)

b)

i) Margin of error ( E ) for 90% confidence interval is, 0.4987

ii) Margin of error ( E ) for 95% confidence interval is, 0.5942

iii) Margin of error ( E ) for 99% confidence interval is, 0.7821