Explore BrainMass

# Statistics - Random sample and confidence interval

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

You are given the sample mean and the sample deviation, Use this information to construct the 90% and 95% confidence intervals for the population mean. Which interval is wider?

A random sample of 38 gas grills has a mean price of \$638.20 and a standard deviation of \$59.80.

a)The 90% confidence interval is __,__ (round to two decimal places)

b)The 95% confidence interval is __,__ (round to two decimal places)

c)Which interval is wider? The 90% or 95% confidence interval? (choose one)

https://brainmass.com/statistics/confidence-interval/statistics-random-sample-confidence-interval-267269

#### Solution Preview

n = 38, x-bar = 638.20, s = 59.80

SE = s/sqrt n = 59.80/sqrt 38 = 9.7008

(a) z = 1.645

The ...

#### Solution Summary

The random sample and confidence intervals are examined. A complete, neat and step-by-step solution is provided.

\$2.19