Purchase Solution

Confidence Interval with Z test

Not what you're looking for?

Ask Custom Question

The Sacred Grounds coffee shop in Deadhorse, AK, is considering replacing its coffee brewing units with new German brewers. You have been assigned to investigate this proposal. Develop a 99% confidence interval for the average yield (cups per pound) for the new German coffee brewer. The margin of error should be no bigger than .3 (three-tenths of a cup). Based on experience with the current system, your best guess for the population standard deviation is 1.2 cups. How big a sample do you need?

Attachments
Purchase this Solution
Solution Summary

This solution is comprised of a detailed explanation of Confidence Interval using Z test. In this solution, all the possible explanation of this complicated topic provides students with a clear perspective of confidence interval.

Purchase this Solution
Free BrainMass Quizzes
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.

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.

View More Free Quizzes
Related BrainMass Solutions

  • Confidence Interval & Hypothesis Testing: Cure Rate

    Do a hypothesis test. Use alpha=0.05. z=0.309 A standard surgery was performed on 50 patients with severe sinus infection, and 36 were cured. Answers a) Find a 95% confidence interval for the population cure rate or proportion.

  • Two sided interval

    346663 T-distribution or CLT: Two sided interval analysis on test score Assume a very large normally distributed population of scores on a test with mean 77 and standard deviation 7. a.

  • Significance Tests and Confidence Intervals

    z test for proportions one-sample z confidence interval for proportions two-sample z test for proportions two-sample z confidence interval for proportions chi-square Please complete at least three significance tests and a confidence interval.

  • Hypothesis Testing & Confidence Interval for Mean

    The confidence interval is given by , where = 51, σ = 6, n = 49, = 1.644853627 That is, = (49.59, 52.41) Since the calculation of confidence interval involves a two tailed z value, 90% confidence interval is exactly a 5% one tailed test.

  • Hypothesis Testing & Confidence Interval

    Proportion 0.023333333 Z Value -1.644853627 Standard Error of the Proportion 0.008715673 Interval Half Width 0.014336007 Confidence Interval Interval Lower Limit 0.008997326 Interval Upper Limit 0.03766934 Thus with 90% confidence we can

  • Confidence interval for mean

    The sample mean is 6.8 hours with a sample standard deviation of 1.1 hours. a. Find the 90% confidence interval for mean (mu). b. Find the 95% confidence interval for mean (mu). 5.

  • Normal Probability, Hypothesis Testing & Confidence Interval

    Proportion 0.2 Z Value -2.575829304 Standard Error of the Proportion 0.016329932 Interval Half Width 0.042063116 Confidence Interval Interval Lower Limit 0.157936884 Interval Upper Limit 0.242063116 Thus with 99% confidence we can claim

  • CI and Hypothesis Test

    The confidence interval has the same assumptions as the statistic used to make it. For example, if you made a confidence interval with a z-value, then the assumptions would be the same as for the z-test.

  • Confidence interval, error of estimate, sample size

    The mean age is 37.4 years with a standard deviation of 10.3 years. a. Find the 99% confidence interval for the mean age. b. What is the error of estimate for the 90% confidence interval? c.

  • Confidence Intervals

    NOTE(2): Since these are large samples with sample size nx=ny=100, we use z-score. Note that we need to find a 90% confidence interval, so, z=1.645. You can use z-table to get it.

View More Related Solutions