535915
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Quiz von hsherwood02, aktualisiert more than 1 year ago
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Erstellt von hsherwood02
vor mehr als 10 Jahre
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Frage 1
Frage
For each of the following three statements, formulate the correct null and alternative hypotheses
The average weight for Santa Clara freshman men is more than 150 pounds
Antworten
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Ho: m = 150 H1: m ≠ 150
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Ho: m = 150 H1: m > 150
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Ho: m < 150 H1: m > 150
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Ho: m > 150 H1: m = 150
Frage 2
Frage
Thirty percent of California teenagers drop out of school
Antworten
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Ho: P ≠ .30 H1: P = .30
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Ho: P = .30 H1: P > .30
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Ho: m = .30 H1: m ≠ .30
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Ho: P = .30 H1: P ≠ .30
Frage 3
Frage
The variance in daily commute time on the Bay Bridge is less than 100 minutes2
Antworten
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Ho: m = 100 H1: m < 100
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Ho: σ = 100 H1: σ ≠ 100
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Ho: σ = 100 H1: σ < 100
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Ho: m = 100 H1: m ≠ 100
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none of these answers
Frage 4
Frage
Suppose that 18 observations are drawn from a normal population whose standard deviation is 12. Given a sample mean of 30.2, answer the following seven questions
Formulate the null and alternative hypotheses to test whether or not the population mean is greater than 25
Antworten
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Ho: X-bar = 25 H1: X-bar ≠ 25
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Ho: m = 25 H1: m > 25
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Ho: X-bar = 25 H1: X-bar > 25
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Ho: m = 25 H1: m ≠ 25
Frage 5
Frage
What is the value of Zcalc
Antworten
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1.84
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1.96
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0.63
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7.80
Frage 6
Frage
What is the value of Zcrit, given a 5% level of significance
Antworten
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±1.96
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1.645
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none of these answers
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1.96
Frage 7
Frage
What is the p-value
Antworten
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.058
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.050
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.967
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.033
Frage 8
Frage
What is the conclusion of the hypothesis test
Antworten
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Do not reject the null since p-value < α
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Reject the null since Zcalc > Zcrit
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Do not reject the null since Zcalc > -Zcrit
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Reject the null since p-value > α
Frage 9
Frage
We want to calculate the probability of a Type II error for this problem given a new μ = 32.
What is the calculated value of X-barcrit
Antworten
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30.15
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21.3
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29.7
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25.0
Frage 10
Frage
What is the calculated value of β
Antworten
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.21
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.15
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.42
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.04
Frage 11
Frage
Using Excel, find the critical value(s) for the Student's t-test for the following three hypothesis tests, where n is the sample size and alpha is the significance level (Hint: Watch your signs and be careful with the number of tails)
Ho: m = 3 and H1: m < 3, n = 7, α = 4%
Antworten
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none of these answers
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-2.10
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2.61
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-2.61
Frage 12
Frage
Ho: m = 12 and H1: m > 12, n = 21, α = 9%
Antworten
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1.39
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2.23
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2.19
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1.78
Frage 13
Frage
Ho: m = 5 and H1: m ¹ 5, n = 50, α = 9%
Antworten
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-1.73, 1.73
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-2.02, 2.02
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-1.30, 1.30
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none of these answers
Frage 14
Frage
Joan's nursery specializes in custom-designed landscaping for residential areas. The estimated labor cost associated with a particular landscaping proposal is based on the number of plantings of trees, shrubs and so on to be used for the project. For cost estimating purposes, managers use two hours of labor time for the planting of medium sized trees. Actual times from a sample of ten plantings during the past month are as follows: 1.7, 1.5, 2.6, 2.2, 2.4, 2.3, 2.6, 3.0, 1.4, 2.3. Assume that the population is normally distributed. Answer the following six questions
Based on this sample, what is the 95% confidence interval for the true mean tree planting time
Antworten
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(1.88, 2.52)
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(1.76, 2.64)
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(1.83, 2.57)
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(1.97, 2.43)
Frage 15
Frage
How do you interpret the above confidence interval
Antworten
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we are 95% confident that 5% of the values of the sample means will result in a confidence interval that includes the population mean
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if we repeatedly draw samples of the same size from the same population, 95% of the intervals we create in this fashion will capture the true population mean
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we are 95% confident that we have selected a sample whose range of values does not contain the population mean
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95% of the data will fall within the confidence interval
Frage 16
Frage
We want to perform a hypothesis test to determine if the mean tree planting time differs from two hours.
Formulate the null and alternative hypotheses
Antworten
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Ho: m = 2 H1: m < 2
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Ho: X-bar = 2 H1: X-bar ≠ 2
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Ho: m = 2 H1: m ≠ 2
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Ho: m < 2 H1: m ≠ 2
Frage 17
Frage
At the 10% significance level, what is the critical value of the test statistic
Antworten
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-1.645, 1.645
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-1.96, 1.96
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-2.262, 2.262
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-1.833, 1.833
Frage 18
Frage
What is the calculated value of the test statistic
Antworten
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1.23
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2.35
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1.36
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2.06
Frage 19
Frage
What is the conclusion of the hypothesis test
Antworten
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Do not reject the null since tcalc < tcrit
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Accept the null since tcalc < tcri
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Do not reject the null since Zcalc < Zcrit
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Reject the null since Zcalc > Zcrit
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