Purchase Solution

Upper and lower confidence intervals: Water treatment example

Not what you're looking for?

Ask Custom Question

Most water treatment facilities monitor the quality of their drinking water on an hourly basis. One variable monitored is pH, which measures the degree of alkalinity or acidity in the water. A target pH level is 8.5. pH values below 8.5 is acidic and above 8.5 is alkaline, both of which are bad for health. A random sample of 20 measurements resulted in an average pH of 8.55 with a standard deviation of 0.28.

a. Does the sample provide sufficient evidence that the mean pH level in the water differs from 8.5? Conduct a test at the ? = .01 level

b. What are the upper and lower limits of the 95% confidence intervals?

Purchase this Solution

Solution Summary

Provides steps necessary to find the upper and lower confidence intervals.

Purchase this Solution

Free BrainMass Quizzes
Measures of Central Tendency

Tests knowledge of the three main measures of central tendency, including some simple calculation questions.

Know Your Statistical Concepts

Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.

Measures of Central Tendency

This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.

Terms and Definitions for Statistics

This quiz covers basic terms and definitions of statistics.