Explore BrainMass

# Confidence Interval; Margin of Error

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

(1) The confidence interval: 5.06 < sigma2 < 23.33 is for the population variance based on the following sample statistics:

n = 25, x-bar = 41.2, and s = 3.1

What is the degree of confidence? Use only integers, no % sign and no decimal places.

(2) Find the margin of error.

95% confidence interval; n = 91 ; x-bar = 55, s = 5.4

Round to the nearest two decimal places.

See attached file for full problem description.

https://brainmass.com/statistics/confidence-interval/102750

#### Solution Preview

13.
The confidence interval: 5.06 < sigma2 < 23.33 is for the population variance based on the following sample statistics:
n = 25, x-bar = 41.2, and s = 3.1

What is the degree of confidence? Use only integers, no % sign and no decimal places.
(Points: 3)

The confidence interval for a population variance is calculated as:

(n - 1)s2 &#8804; &#963;2 &#8804; (n - 1)s2
X2&#945;/2, n - 1 X21- &#945;/2, n - 1

The X2&#945;/2, n - 1 and the X21- &#945;/2, n - 1 are critical values from the chi-squared distribution. We'll find them in a minute.

From the problem, we know that the left side of the inequality is equal to 5.06 and the ...

\$2.19