In this problem, assume that the distribution of differences is approximately normal. Note: For degrees of freedom d.f. not in the Student's t-table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more "conservative" answer. In environmental studies, sex ratios are of great importance. Wolf society, packs, and ecology have been studied extensively at different locations in the U.S. and foreign countries. Sex ratios for eight study sites in northern Europe are shown below. Location of Wolf Pack % Males (Winter) % Males (Summer) Finland 88 69 Finland 35 39 Finland 83 65 Lapland 55 48 Lapland 64 55 Russia 50 50 Russia 41 50 Russia 5 45 It is hypothesized that in winter, "loner" males (not present in summer packs) join the pack to increase survival rate. Use a 5% level of significance to test the claim that the average percentage of males in a wolf pack is higher in winter. (Let

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
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In this problem, assume that the distribution of differences is approximately normal. Note: For degrees of freedom d.f. not in the
Student's t-table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small
amount and therefore produce a slightly more "conservative" answer.
In environmental studies, sex ratios are of great importance. Wolf society, packs, and ecology have been studied extensively at
different locations in the U.S. and foreign countries. Sex ratios for eight study sites in northern Europe are shown below.
Location of Wolf Pack
% Males (Winter)
% Males (Summer)
Finland
88
69
Finland
35
39
Finland
83
65
Lapland
55
48
Lapland
64
55
Russia
50
50
Russia
41
50
Russia
55
45
It is hypothesized that in winter, "loner" males (not present in summer packs) join the pack to increase survival rate. Use a 5%
level of significance to test the claim that the average percentage of males in a wolf pack is higher in winter. (Let
d = winter - summer.)
(a) What is the level of significance?
State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test?
Ho: Ma - 0; H,: Hg < 0; left-tailed
O Ho: Ha - 0; H,: H > 0; right-tailed
O Ho: Ha > 0; H: Ha - 0; right-tailed
Ho: Ha- 0; H: Hg 0; two-tailed
(b) What sampling distribution will you use? What assumptions are you making?
O The standard normal. We assume that d has an approximately uniform distribution.
O The standard normal. We assume that d has an approximately normal distribution.
The Student's t. We assume that d has an approximately uniform distribution.
O The Student's t. We assume that d has an approximately normal distribution.
What is the value of the sample test statistic? (Round your answer to three decimal places.)
(c) Find (or estimate) the P-value.
O P-value > 0.250
O 0.125 < P-value < 0.250
O 0.100 < P-value < 0.125
O 0.075 < P-value < 0.100
O 0.050 < P-value < 0.075
O P-value < 0.050
Sketch the sampling distribution and show the area corresponding to the P-value.
A plot of the sampling distribution probability curve has a
horizontal axis with values from -4 to 4. The curve enters the
window from the left, just above the horizontal axis, goes up and
to the right, changes direction over approximately 0 on the
horizontal axis, and then goes down and to the right before exiting
the window just above the horizontal axis. The area under the
O-4
-2
QO curve between -1.768 and 4 is shaded.
-2
(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically
significant at level a?
O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant.
O At the a = 0.05 level, we reject the null hypothesis and conclude the data are statistically significant.
At the a = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant.
O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.
Transcribed Image Text:In this problem, assume that the distribution of differences is approximately normal. Note: For degrees of freedom d.f. not in the Student's t-table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more "conservative" answer. In environmental studies, sex ratios are of great importance. Wolf society, packs, and ecology have been studied extensively at different locations in the U.S. and foreign countries. Sex ratios for eight study sites in northern Europe are shown below. Location of Wolf Pack % Males (Winter) % Males (Summer) Finland 88 69 Finland 35 39 Finland 83 65 Lapland 55 48 Lapland 64 55 Russia 50 50 Russia 41 50 Russia 55 45 It is hypothesized that in winter, "loner" males (not present in summer packs) join the pack to increase survival rate. Use a 5% level of significance to test the claim that the average percentage of males in a wolf pack is higher in winter. (Let d = winter - summer.) (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test? Ho: Ma - 0; H,: Hg < 0; left-tailed O Ho: Ha - 0; H,: H > 0; right-tailed O Ho: Ha > 0; H: Ha - 0; right-tailed Ho: Ha- 0; H: Hg 0; two-tailed (b) What sampling distribution will you use? What assumptions are you making? O The standard normal. We assume that d has an approximately uniform distribution. O The standard normal. We assume that d has an approximately normal distribution. The Student's t. We assume that d has an approximately uniform distribution. O The Student's t. We assume that d has an approximately normal distribution. What is the value of the sample test statistic? (Round your answer to three decimal places.) (c) Find (or estimate) the P-value. O P-value > 0.250 O 0.125 < P-value < 0.250 O 0.100 < P-value < 0.125 O 0.075 < P-value < 0.100 O 0.050 < P-value < 0.075 O P-value < 0.050 Sketch the sampling distribution and show the area corresponding to the P-value. A plot of the sampling distribution probability curve has a horizontal axis with values from -4 to 4. The curve enters the window from the left, just above the horizontal axis, goes up and to the right, changes direction over approximately 0 on the horizontal axis, and then goes down and to the right before exiting the window just above the horizontal axis. The area under the O-4 -2 QO curve between -1.768 and 4 is shaded. -2 (d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level a? O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant. O At the a = 0.05 level, we reject the null hypothesis and conclude the data are statistically significant. At the a = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant. O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.
Finland
35
39
Finland
83
65
Lapland
55
48
Lapland
64
55
Russia
50
50
Russia
41
50
Russia
55
45
It is hypothesized that in winter, "loner" males (not present in summer packs) join the pack to increase survival rate. Use a 5%
level of significance to test the claim that the average percentage of males in a wolf pack is higher in winter. (Let
d= winter - summer.)
(a) What is the level of significance?
State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test?
O Ho: Hg- 0; H: H< 0; left-tailed
O Ho: Ha- 0; H,: g > 0; right-tailed
O Họ: Hg > 0; H,: M- 0; right-tailed
O Ho: Ha- 0; H,: g* 0; two-tailed
(b) What sampling distribution will you use? What assumptions are you making?
O The standard normal. We assume that d has an approximately uniform distribution.
The standard normal. We assume that d has an approximately normal distribution.
O The Student's t. We assume that d has an approximately uniform distribution.
O The Student's t. We assume that d has an approximately normal distribution.
What is the value of the sample test statistic? (Round your answer to three decimal places.)
(c) Find (or estimate) the P-value.
O P-value > 0.250
O 0.125 < P-value < 0.250
0.100 < P-value < 0.125
O
O 0.075 < P-value < 0.100
O 0.050 < P-value < 0.075
O P-value < 0.050
Sketch the sampling distribution and show the area corresponding to the P-value.
-2
2
A plot of the sampling distribution probability curve has a
horizontal axis with values from -4 to 4. The curve enters the
window from the left, just above the horizontal axis, goes up and
to the right, changes direction over approximately o on the
horizontal axis, and then goes down and to the right before exiting
the window just above the horizontal axis. The area under the
curve between -4 and -1.768 as well as the area under the curve
DO between 1.768 and 4 are both shaded.
(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically
significant at level a?
O At the a - 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant.
O At the a- 0.05 level, we reject the null hypothesis and conclude the data are statistically significant.
O At the a = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant.
O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.
(e) State your conclusion in the context of the application.
O Reject the null hypothesis, there is sufficient evidence to claim that the average percentage of male wolves in winter is
higher.
O Fail to reject the null hypothesis, there is insufficient evidence to claim that the average percentage of male wolves in
winter is higher.
O Fail to reject the null hypothesis, there is sufficient evidence to claim that the average percentage of male wolves in
winter is higher.
O Reject the null hypothesis, there is insufficient evidence to claim that the average percentage of male wolves in winter
is higher.
Transcribed Image Text:Finland 35 39 Finland 83 65 Lapland 55 48 Lapland 64 55 Russia 50 50 Russia 41 50 Russia 55 45 It is hypothesized that in winter, "loner" males (not present in summer packs) join the pack to increase survival rate. Use a 5% level of significance to test the claim that the average percentage of males in a wolf pack is higher in winter. (Let d= winter - summer.) (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test? O Ho: Hg- 0; H: H< 0; left-tailed O Ho: Ha- 0; H,: g > 0; right-tailed O Họ: Hg > 0; H,: M- 0; right-tailed O Ho: Ha- 0; H,: g* 0; two-tailed (b) What sampling distribution will you use? What assumptions are you making? O The standard normal. We assume that d has an approximately uniform distribution. The standard normal. We assume that d has an approximately normal distribution. O The Student's t. We assume that d has an approximately uniform distribution. O The Student's t. We assume that d has an approximately normal distribution. What is the value of the sample test statistic? (Round your answer to three decimal places.) (c) Find (or estimate) the P-value. O P-value > 0.250 O 0.125 < P-value < 0.250 0.100 < P-value < 0.125 O O 0.075 < P-value < 0.100 O 0.050 < P-value < 0.075 O P-value < 0.050 Sketch the sampling distribution and show the area corresponding to the P-value. -2 2 A plot of the sampling distribution probability curve has a horizontal axis with values from -4 to 4. The curve enters the window from the left, just above the horizontal axis, goes up and to the right, changes direction over approximately o on the horizontal axis, and then goes down and to the right before exiting the window just above the horizontal axis. The area under the curve between -4 and -1.768 as well as the area under the curve DO between 1.768 and 4 are both shaded. (d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level a? O At the a - 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant. O At the a- 0.05 level, we reject the null hypothesis and conclude the data are statistically significant. O At the a = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant. O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant. (e) State your conclusion in the context of the application. O Reject the null hypothesis, there is sufficient evidence to claim that the average percentage of male wolves in winter is higher. O Fail to reject the null hypothesis, there is insufficient evidence to claim that the average percentage of male wolves in winter is higher. O Fail to reject the null hypothesis, there is sufficient evidence to claim that the average percentage of male wolves in winter is higher. O Reject the null hypothesis, there is insufficient evidence to claim that the average percentage of male wolves in winter is higher.
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