Explore BrainMass

Explore BrainMass

    Question about Confidence interval and t test

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

    Part 1

    Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 773 kernels and put them in a popper. After popping, 66 unpopped kernels were counted.

    A. Construct a 90% confidence interval for the proportion of all kernels that would not pop.
    1. What was the Point Estimate?

    2. What was the Margin of error, E =

    3. What was the z-value?

    4. Confidence Interval?
    (write as 0.089 < µ < 0.125)

    B. Interpret the confidence interval

    C. Check the normality assumption.

    Part 2
    sample of 19 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages. On each page, the mean area devoted to display ads was measured (a display ad is a large block of multicolored illustrations, maps, and text).

    Construct a 95% confidence interval. The data are shown below:

    0 260 356 350 536 0 268 369 428 536
    268 396 469 536 162 338 350 536 536
    (in square millimeters)

    A. Construct a 95% confidence interval for the true mean.
    1. What was the Point Estimate?

    2. What was the Margin of error, E =

    3. What was the t-value?

    4. Confidence Interval?
    (write as 23 < µ < 45)

    B. Interpret the confidence interval

    C. What sample size, n, would be needed to obtain an error of ±10 square millimeters with 99% confidence?
    (Use Sample Size for a Mean, Doane, Ch. 8, p. 326 and s in place of &#963;)
    1. Sample size, n = [(z)(s)/E]^2

    2. What is the sample size, n, using the finite formula?
    (N = 1,591 pages)
    Sample size, n =

    Part 3
    Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below.

    The firm examined 45 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard deviation, s = 4.45 pages. Is the true mean greater than 10 at a 99% confidence level?

    A. Choose the Hypothesis

    B. Specify the Decision Rule

    C. Calculate the Test Statistic

    D. Make the Decision

    E. Give an interpretation of the Decision

    F. P-value Method
    1. Calculate the P-value. What is it?
    (There are online calculators or MegaStat)

    2. Does that P-value support the Decision in Part D? Explain.

    HYPOTHESIS TEST ~ PROPORTIONS
    Part 4

    Read and understand before responding
    + Lecture Notes

    A coin was flipped 80 times and came up heads 50 times. Is the coin biased toward heads at a 90% confidence level?

    A. Choose the Hypothesis

    B. Specify the Decision Rule

    C. Calculate the Test Statistic

    D. Make the Decision

    E. Give an interpretation of the Decision

    F. P-value Method
    1. Calculate the P-value. What is it?

    2. Does that P-value support the Decision in Part D? Explain.

    © BrainMass Inc. brainmass.com June 3, 2020, 10:19 pm ad1c9bdddf
    https://brainmass.com/statistics/students-t-test/225900

    Solution Summary

    The solution provides step by step method for the calculation of confidence interval and t test. Formula for the calculation and Interpretations of the results are also included.

    $2.19

    ADVERTISEMENT