# Confidence Interval: Sampling Soybean Meal

A sampling of a lot of soybean meal gave the following composition for Lysine in (grams/kilogram):

22.2

24.8

24.7

26.5

20.9

23.8

26.0

25.6

27.0

23.9

Do the following:

a) Construct a 99% two sided confidence interval for (std. deviation)^2.

b) Calculate a 99% lower confidence bound for (std deviation)^2.

c) Calculate a 90% lower confidence bound for (std deviation).

d) Compare the intervals computed.

https://brainmass.com/statistics/confidence-interval/confidence-interval-sampling-soybean-meal-192517

#### Solution Preview

(a) Variance for the given data = (sigma)^2 = 3.658

Standard error of (sigma)^2 = SE = (sigma)^2 * sqrt(2/n) = 3.658 * sqrt(2/10) = 1.636

The 99% CI for the variance = [variance - 2.576 * SE, ...

#### Solution Summary

In about 160 words, a neat, step-by-step solution is provided which outlines how to construct a two-sided confidence interval and lower confidence bound. All calculations are provided.