Purchase Solution

Determining Sample Size to estimate mean electric bill

Not what you're looking for?

Ask Custom Question

A consumer group wants to estimate the mean electric bill for the month of July for single family-homes in a large city. Based on studies conducted in other cities, the standard deviation is assumed to be $25. The group wants to estimate the mean bill for July to within + or - $5 with 99% confidence.

a. What sample size is needed?

b. If 95% of confidence is desired, how many homes need to be selected?

Purchase this Solution
Solution Summary

This solution explains how to determine the sample size required for the given study.

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.

Terms and Definitions for Statistics

This quiz covers basic terms and definitions of statistics.

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.

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.

View More Free Quizzes
Related BrainMass Solutions

  • Confidence Interval & Sample Size

    Discuss the effect of sample size on confidence interval estimate. Q8.4 A consumer group wants to estimate the mean of electric bill for the month of July for single family homes in a large city.

  • Probability of Proportions

    A group of investors wants to develop a chain of fast-food restaurants. In determining potential costs for each facility, they must consider, among other expenses, the average monthly electric bill.

  • Sample size, confidence interval and hypothesis testing

    Media research wants to estimate the man amount of time (in minutes) that full time college students spend watching television each weekday. Find the sample size necessary to estimate that mean with a a 15 min margin of error.

  • Estimating Population Values

    He has selected a simple random sample of 200 sales receipts from the past year's receipts and has calculated the mean and standard deviation for the dollar amount of each bill that was allocated to appetizers.

  • Western Electric runs rule

    size is 150, sample proportion above 0.0579 indicates that the process is not in statistical control.

  • Interval estimates and differences

    Is the size of the population relevant when one is determining the sample size for a confidence interval? What is necessary to determine the sample size? 3.

  • Determining Minimum Sample Size

    Estimate the minimum sample size required to estimate the population mean with stated accuracy. The minimum sample size required to estimates the population mean with a stated accuracy is_____ (Round to the nearest integer as needed). Solution.

  • Calculating Confidence Interval Estimate for True Mean

    This solution describes the steps for determining confidence interval estimate for true mean weight of bags.

  • How Many Test Runs for a Sample Size?

    83139 How Many Test Runs for a Sample Size? The manufacturer of batteries used in small electric appliances wants to establish the average life of a battery.

View More Related Solutions