Section 9.2 Question #8 Listed below are time intervals (min) between eruptions of a geyser. Assume that the "recent" times are within the past few years, the "past" times are from around 20 years ago, and that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Does it appear that the mean time interval has changed? Is the conclusion affected by whether the significance level is 0.10 or 0.01? Recent 77 91 90 78 57 100 61 87 69 89 83 83 55 81 73 101 61 Past 90 89 93 94 64 85 85 92 88 91 89 91 Let μ1 be the recent times and let μ2 be the past times. What are the null and alternative hypotheses? A. H0: μ1 = μ2 H1: μ1 ≠ μ2 B. H0: μ1 < μ2 H1: μ1 = μ2 C. H0: μ1 = μ2 H1: μ1 > μ2 D. H0: μ1 ≠ μ2 H1: μ1 = μ2 Calculate the test statistic. t= _____________ (Round to two decimal places as needed.) Find the P-value. P-value= ____________ (Round to three decimal places as needed.) Make a conclusion about the null hypothesis and a final conclusion that addresses the original claim. Use a significance level of 0.10. ______________ ( A. Fail to reject, B. Reject ) H0 because the P-value is ____________ ( A. less than or equal to, B. greater than ) the significance level. There ___________ ( A. is, B. is not ) sufficient evidence that the mean time interval has changed. Is the conclusion affected by whether the significance level is 0.10 or 0.01? A. No, the conclusion is not affected by the significance level because H0 is rejected regardless of whether a significance level of 0.10 or 0.01 is used. B. No, the conclusion is not affected by the significance level because H0 is not rejected regardless of whether a significance level of 0.10 or 0.01 is used. C. Yes, the conclusion is affected by the significance level because H0 is rejected when the significance level is 0.10 but is not rejected when the significance level is 0.01. D. Yes, the conclusion is affected by the significance level because H0 is rejected when the significance level is 0.01 but is not rejected when the significance level is 0.10.
Section 9.2
Question #8
Listed below are time intervals (min) between eruptions of a geyser. Assume that the "recent" times are within the past few years, the "past" times are from around 20 years ago, and that the two samples are independent simple random samples selected from
|
Recent
|
77
|
91
|
90
|
78
|
57
|
100
|
61
|
87
|
69
|
89
|
83
|
83
|
55
|
81
|
73
|
101
|
61
|
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Past
|
90
|
89
|
93
|
94
|
64
|
85
|
85
|
92
|
88
|
91
|
89
|
91
|
Let μ1 be the recent times and let μ2 be the past times. What are the null and alternative hypotheses?
A. H0: μ1 = μ2
H1: μ1 ≠ μ2
B. H0: μ1 < μ2
H1: μ1 = μ2
C. H0: μ1 = μ2
H1: μ1 > μ2
D. H0: μ1 ≠ μ2
H1: μ1 = μ2
Calculate the test statistic.
t= _____________ (Round to two decimal places as needed.)
Find the P-value.
P-value= ____________ (Round to three decimal places as needed.)
Make a conclusion about the null hypothesis and a final conclusion that addresses the original claim. Use a significance level of 0.10.
______________ ( A. Fail to reject, B. Reject ) H0 because the P-value is ____________ ( A. less than or equal to, B. greater than ) the significance level. There ___________ ( A. is, B. is not ) sufficient evidence that the mean time interval has changed.
Is the conclusion affected by whether the significance level is 0.10 or 0.01?
A. No, the conclusion is not affected by the significance level because H0 is rejected regardless of whether a significance level of 0.10 or 0.01 is used.
B. No, the conclusion is not affected by the significance level because H0 is not rejected regardless of whether a significance level of 0.10 or 0.01 is used.
C. Yes, the conclusion is affected by the significance level because H0 is rejected when the significance level is 0.10 but is not rejected when the significance level is 0.01.
D. Yes, the conclusion is affected by the significance level because H0 is rejected when the significance level is 0.01 but is not rejected when the significance level is 0.10.
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