福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

傻子爱傻妞

傻子爱傻妞 发表于 23-11-2013 23:19
福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

http://bbs.sgchinese.net/forum.php?mod=viewthread&tid=7481334

nancy_1129

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傻子爱傻妞

福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

猥亵男青年

福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

猥亵男青年

猥亵男青年 发表于 24-11-2013 09:43
福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

猥亵男青年

猥亵男青年 发表于 24-11-2013 11:42

福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

猥亵男青年

猥亵男青年 发表于 24-11-2013 13:35
福信家园招寄宿学生 近杜佛，金文泰，Nexus 国际学校

The sample has mean ¯ x = 1.243 and standard deviation s = 0.448.
a. We wish to test
H 0 : µ = 1,
H 1 : µ > 1.
The test statistic has value
t 0 =
¯ x − 1
s/ √ n
=
1.243 − 1
0.448/ √ 20
= 2.43.
Because t 0 < t 0.01,19 = 2.539, we fail to reject H 0 at the 0.01 significance level. So there is
insufficient evidence, at the α = 0.01 level, to conclude that the population mean expense
ratio for large-cap growth mutual funds exceeds 1%.
b. Since we failed to reject H 0 in part (a) and in fact µ = 1.33 > 1, we have committed a type II
error.
c. By the formula on page 40 of Lecture 6,
β = Φ
?
z α −
δ √ n
σ
?
= Φ
?
2.33 −
(1.33 − 1) √ 20
0.5
?
= Φ(−0.62) = 0.2676.
So the power of the test is 1 − β = 0.7324.

nancy_1129

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猥亵男青年

猥亵男青年 发表于 24-11-2013 16:31
The sample has mean ¯ x = 1.243 and standard deviation s = 0.448.
a. We wish to test
H 0 : µ = 1 ...

The sample has mean ¯ x = 1.243 and standard deviation s = 0.448.
a. We wish to test
H 0 : µ = 1,
H 1 : µ > 1.
The test statistic has value
t 0 =
¯ x − 1
s/ √ n
=
1.243 − 1
0.448/ √ 20
= 2.43.
Because t 0 < t 0.01,19 = 2.539, we fail to reject H 0 at the 0.01 significance level. So there is
insufficient evidence, at the α = 0.01 level, to conclude that the population mean expense
ratio for large-cap growth mutual funds exceeds 1%.
b. Since we failed to reject H 0 in part (a) and in fact µ = 1.33 > 1, we have committed a type II
error.
c. By the formula on page 40 of Lecture 6,
β = Φ
?
z α −
δ √ n
σ
?
= Φ
?
2.33 −
(1.33 − 1) √ 20
0.5
?
= Φ(−0.62) = 0.2676.
So the power of the test is 1 − β = 0.7324.

猥亵男青年

猥亵男青年 发表于 24-11-2013 17:53
The sample has mean ¯ x = 1.243 and standard deviation s = 0.448.
a. We wish to test
H 0 : µ = 1 ...

The sample has mean ¯ x = 1.243 and standard deviation s = 0.448.
a. We wish to test
H 0 : µ = 1,
H 1 : µ > 1.
The test statistic has value
t 0 =
¯ x − 1
s/ √ n
=
1.243 − 1
0.448/ √ 20
= 2.43.
Because t 0 < t 0.01,19 = 2.539, we fail to reject H 0 at the 0.01 significance level. So there is
insufficient evidence, at the α = 0.01 level, to conclude that the population mean expense
ratio for large-cap growth mutual funds exceeds 1%.
b. Since we failed to reject H 0 in part (a) and in fact µ = 1.33 > 1, we have committed a type II
error.
c. By the formula on page 40 of Lecture 6,
β = Φ
?
z α −
δ √ n
σ
?
= Φ
?
2.33 −
(1.33 − 1) √ 20
0.5
?
= Φ(−0.62) = 0.2676.
So the power of the test is 1 − β = 0.7324.