Explore BrainMass

Explore BrainMass

    Null hypothesis, decision rule, two-tailed test, z value

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

    6
    Marks: 1 Please answer questions 6 - 9 based on the following information.

    A firm has an order process time of at least 20 minutes. After a change in the process, a researcher wishes to determine if the processing time for orders in a warehouse averages less than 20 minutes, at a 99% confidence level. The researcher uses a sample of 80 orders from a monthly run of 10,000 orders and determines a sample mean of 19 minutes with a standard deviation of 3 minutes.
    The null hypothesis is:

    Choose one answer.
    a. H1 : μ = 20 minutes
    b. H0 : μ = 20 minutes
    c. H0 : μ >20 minutes
    d. H0 : &#956; <20 minutes
    ..

    7
    Marks: 1 This is an example of a:
    Choose one answer.
    a. an upper-tailed test.
    b. a lower-tailed test.
    c. a two-tailed test.
    ..

    8
    Marks: 1 The decision rule is:
    Choose one answer.
    a. Fail to reject H0 if z is between -2.58 and +2.58; reject otherwise.
    b. Fail to reject H0 if z is between -1.96 and +1.96; reject otherwise.
    c. Fail to reject H0 if z is > +2.33; reject otherwise.
    d. Fail to reject H0 if z is < -2.33; reject otherwise.
    e. Fail to reject H0 if z is > -2.33; reject otherwise.
    ..

    9
    Marks: 1 The researcher should reject the null hypothesis.
    Choose one answer.
    a. True
    b. False
    ..

    10
    Marks: 1 Please answer questions 10-12 using the following information.
    A sample of 60 observations yields a mean of 160 and a sample standard deviation of 40. A sample of 50 observations of another population yields a mean of 149 and a sample standard deviation of 38. A test at the &#945; = 0.05 level of significance is performed for
    H0 : µ 1&#8804; µ2 ; H1 : µ1 > µ2 .

    This is an example of a(n):
    Choose one answer.
    a. lower-tailed test.
    b. upper-tailed test.
    c. two-tailed test.
    ..

    11
    Marks: 1 The value of the test statistic and p-value are, respectively,:
    Choose one answer.
    a. 1.48, 0.0694
    b. 1.61, 0.027
    c. 1.96, 0.035
    d. 2.28, 0.537
    ..

    12
    Marks: 1 The results indicate that the null hypothesis should:
    Choose one answer.
    a. be rejected.
    b. not be rejected.
    ..

    13
    Marks: 1 Please answer questions 13 and 14 using the following information.
    A report indicates that readership of a home improvement magazine is split evenly among men and women. A random sample of 600 subscribers identifies that 330 are women. The results are tested at the ? = 0.05 level of significance that the report is false.

    The null hypothesis and computed value for this problem are, respectively,:
    Choose one answer.
    a. H0 : &#956; <0.50; z = 0.46
    b. H0 : &#956; = 0.50; z = 1.96
    c. H0 : &#960; = 0.50; z = 2.45
    d. H0 : &#956; &#8800; 300; z = 2.58
    ..

    14
    Marks: 1 We should conclude that the report is false.
    Choose one answer.
    a. True.
    b. False
    ..

    15
    Marks: 1 Please answer questions 15 and 16 using the following information.
    In a sample of its readership, 144 of 300 readers in one income bracket approved of the editorial positions of a newspaper. In a different income bracket, 224 of 400 readers approved of the editorial positions. The newspaper wishes to determine if there is a significant difference between the approval rates at an &#945; = 0.05 level of significance.

    The computed value of z is:
    Choose one answer.
    a. 1.645
    b. 1.96
    c. 2.02
    d. 2.1
    e. 55.55
    ..

    16
    Marks: 1 The test results indicate that there is a significant difference between the approval rates of the separate income brackets.
    Choose one answer.
    a. True
    b. False
    ..

    17
    Marks: 1 The student t distribution:
    Choose one answer.
    a. is preferred over the normal distribution for very large size samples.
    b. tends to coincide with the normal distribution for large sample sizes.
    c. resembles a curve that is heavily skewed to the left.
    d. both a and c.
    e. none of the above.
    ..

    18
    Marks: 1 The student t distribution will tend to lead to less Type I errors for small samples.
    Choose one answer.
    a. True
    b. False
    ..

    19
    Marks: 1 For a lower-tailed test, when the sample mean is 50, the null hypothesis mean is 52.5, s = 7 and n = 25; the student t statistic is:
    Choose one answer.
    a. 2.091
    b. -1.79
    c. -2.5
    d. 1.63
    ..

    20
    Marks: 1 For sample A, n = 12 and s2 = 240; for sample B, n = 18 and s2 = 360. The pooled variance of the samples is:
    Choose one answer.
    a. 20
    b. 300
    c. 312.86
    d. 350.76
    e. not calculable without additional data.
    ..

    21
    Marks: 1 Please answer questions 21 and 22 based on the following information.
    Procedure 1:n = 6; &#963;= 10; s2 = 8;
    Procedure 2:n = 6; &#963; = 14; s2 = 12;

    The number of degrees of freedom for the t statistic is:
    Choose one answer.
    a. 5
    b. 10
    c. 11
    d. 12
    ..

    22
    Marks: 1 The pooled variance and t statistic are, respectively :
    Choose one answer.
    a. 10; -2.19
    b. 12; -0.8
    c. 12.5; 1.2
    d. 15; 1.0
    ..

    © BrainMass Inc. brainmass.com June 3, 2020, 11:54 pm ad1c9bdddf
    https://brainmass.com/statistics/hypothesis-testing/null-hypothesis-decision-rule-two-tailed-test-value-307356

    Solution Preview

    Please see attached file.

    The answers and the explanations are in highlighted blue. I attached both doc and docx files, both of which have the same answers.

    6
    Marks: 1 Please answer questions 6 - 9 based on the following information.
    A firm has an order process time of at least 20 minutes. After a change in the process, a researcher wishes to determine if the processing time for orders in a warehouse averages less than 20 minutes, at a 99% confidence level. The researcher uses a sample of 80 orders from a monthly run of 10,000 orders and determines a sample mean of 19 minutes with a standard deviation of 3 minutes.
    The null hypothesis is:

    Choose one answer.
    a. H1 : μ = 20 minutes
    b. H0 : μ = 20 minutes
    c. H0 : μ >20 minutes
    d. H0 : μ <20 minutes
    ..

    7
    Marks: 1 This is an example of a:
    Choose one answer.
    a. an upper-tailed test.
    b. a lower-tailed test.
    c. a two-tailed test.
    Explanation: This is because H1 : μ <20 minutes

    8
    Marks: 1 The decision rule is:
    Choose one answer.
    a. Fail to reject H0 if z is between -2.58 and +2.58; reject otherwise.
    b. Fail to reject H0 if z is between -1.96 and +1.96; reject otherwise.
    c. Fail to reject H0 if z is > +2.33; reject otherwise.
    d. Fail to reject H0 if z is < -2.33; reject otherwise.
    e. Fail to reject H0 if z is > -2.33; reject otherwise.
    ..
    Explanation:
    The rejection region of H0 with 99% confidence level is
    Z< - 2.33.
    9
    Marks: 1 The researcher should reject the null hypothesis.
    Choose one answer.
    a. True ...

    Solution Summary

    The expert examines null hypothesis, decision rules, two tailed tests and z values.

    $2.19

    ADVERTISEMENT