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 | 64 | 53 |
Finland | 64 | 67 |
Finland | 68 | 61 |
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.
What is the value of the sample test statistic? (Round your answer to three decimal places.)
The statistical software output for this problem is:
Paired T hypothesis test:
μD = μ1 - μ2 : Mean of the
difference between % Males (Winter) and % Males (Summer)
H0 : μD = 0
HA : μD ≠ 0
Hypothesis test results:
Difference | Mean | Std. Err. | DF | T-Stat | P-value |
---|---|---|---|---|---|
% Males (Winter) - % Males (Summer) | 4 | 2.542496 | 7 | 1.5732572 | 0.1597 |
Hence,
Sample test statistic = 1.573
In this problem, assume that the distribution of differences is approximately normal. Note: For degrees of...
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...
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...
A.) Let x be a random variable representing dividend yield of bank stocks. We may assume that x has a normal distribution with ? = 2.0%. A random sample of 10 bank stocks gave the following yields (in percents). 5.7 4.8 6.0 4.9 4.0 3.4 6.5 7.1 5.3 6.1 The sample mean is x = 5.38%. Suppose that for the entire stock market, the mean dividend yield is ? = 4.4%. Do these data indicate that the dividend yield of...
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. At five weather stations on Trail Ridge Road in Rocky Mountain National Park, the peak wind gusts (in miles per hour) for January and April are...
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. At five weather stations on Trail Ridge Road in Rocky Mountain National Park, the peak wind gusts (in miles per hour) for January and April are...
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. A survey of houses and traditional hogans was made in a number of different regions of the modern Navajo Indian Reservation. The following table is the...
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 increase the P-value by a small amount and therefore produce a slightly more "conservative" answer Is fishing better from a boat or from the shore? Pyramid Lake is located on the Palute Indian Reservation in Nevada. Presidents, movie stars, and people who just want to catch fish...
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 of that is smaller In some situations, this choice of d.l. may increase the P-value by a small amount and therefore produce a slightly more "conservative answer A survey of houses and traditional hogans was made in a number of different regions of the modern Navajo Indian Reservation. The following table is the...
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. Is fishing better from a boat or from the shore? Pyramid Lake is located on the Paiute Indian Reservation in Nevada. Presidents, movie stars, and people...
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./. that is smaller. In some situations, this choice of d.l. may increase the P-value by a small amount and therefore produce a slightly more conservative answer Is fishing better from a boat or from the shore? Pyramid Lake is located on the Palute Indian Reservation in Nevada, Presidents, movie stars, and people...