Complete parts (a) through (c) below.

(a) Determine the critical value(s) for a right-tailed test of a population mean at the

=0.05

level of significance with

10

degrees of freedom.

(b) Determine the critical value(s) for a left-tailed test of a population mean at the

=0.10

level of significance based on a sample size of

n=20.

(c) Determine the critical value(s) for a two-tailed test of a population mean at the

=0.05

level of significance based on a sample size of

n=17.

Question content area bottom

Part 1

(a)

tcrit=

minus

plus+

plus or minus

enter your response here

(Round to three decimal places as needed.)

Part 2

(b)

tcrit=

minus

plus or minus

plus+

enter your response here

(Round to three decimal places as needed.)

Part 3

(c)

tcrit=

plus or minus

minus

plus+

enter your response here

(Round to three decimal places as needed.)

Several years ago, the mean height of women 20 years of age or older was

63.7

inches. Suppose that a random sample of

45

women who are 20 years of age or older today results in a mean height of

64.2

inches.

(a) State the appropriate null and alternative hypotheses to assess whether women are taller today.

(b) Suppose the P-value for this test is

0.03.

Explain what this value represents.

(c) Writea conclusion for this hypothesis test assuming an

=0.05

level of significance.

Question content area bottom

Part 1

(a) State the appropriate null and alternative hypotheses to assess whether women are taller today.

A.

H0:

=63.7

in. versus

H1:

<63.7

in.

B.

H0:

=64.2

in. versus

H1:

>64.2

in.

C.

H0:

=63.7

in. versus

H1:

>63.7

in.

D.

H0:

=63.7

in. versus

H1:

63.7

in.

E.

H0:

=64.2

in. versus

H1:

64.2

in.

F.

H0:

=64.2

in. versus

H1:

<64.2

in.

Part 2

(b) Suppose the P-value for this test is

0.03.

Explain what this value represents.

A.

There is a

0.03

probability of obtaining a sample mean height of exactly

64.2

inches from a population whose mean height is

63.7

inches.

B.

There is a

0.03

probability of obtaining a sample mean height of

64.2

inches or shorter from a population whose mean height is

63.7

inches.

C.

There is a

0.03

probability of obtaining a sample mean height of

63.7

inches or taller from a population whose mean height is

64.2

inches.

D.

There is a

0.03

probability of obtaining a sample mean height of

64.2

inches or taller from a population whose mean height is

63.7

inches.

Part 3

(c) Writea conclusion for this hypothesis test assuming an

=0.05

level of significance.

A.

Donotreject

the null hypothesis. There

isnot

sufficient evidence to conclude that the mean height of women 20 years of age or older is greater today.

B.

Reject

the null hypothesis. There

is

sufficient evidence to conclude that the mean height of women 20 years of age or older is greater today.

C.

Donotreject

the null hypothesis. There

is

sufficient evidence to conclude that the mean height of women 20 years of age or older is greater today.

D.

Reject

the null hypothesis. There

isnot

sufficient evidence to conclude that the mean height of women 20 years of age or older is greater today.

Determine the critical values for these tests of a population standard deviation.

(a) A right-tailed test with

11

degrees of freedom at the

=0.01

level of significance

(b) A left-tailed test for a sample of size

n=24

at the

=0.1

level of significance

(c) A two-tailed test for a sample of size

n=26

at the

=0.1

level of significance.

Question content area bottom

Part 1

(a) The critical value for this right-tailed test is

enter your response here.

(Round to three decimal places as needed.)

Part 2

(b) The critical value for this left-tailed test is

enter your response here.

(Round to three decimal places as needed.)

Part 3

(c) The critical values for this two-tailed test are

enter your response here.

(Round to three decimal places as needed. Use a comma to separate answers as needed.)

Suppose a mutual fund qualifies as having moderate risk if the standard deviation of its monthly rate of return is less than

4%.

A mutual-fund rating agency randomly selects

29

months and determines the rate of return for a certain fund. The standard deviation of the rate of return is computed to be

3.58%.

Is there sufficient evidence to conclude that the fund has moderate risk at the

=0.01

level of significance? A normal probability plot indicates that the monthly rates of return are normally distributed.

Question content area bottom

Part 1

What are the correct hypotheses for this test?

The null hypothesis is

H0:

sigma

pp

mu

not equals

greater than>

less than<

equals=

0.0358.

0.04.

The alternative hypothesis is

H1:

mu

sigma

pp

greater than>

not equals

equals=

less than<

0.04.

0.0358.

Part 2

Calculate the value of the test statistic.

20=enter your response here

(Round to two decimal places as needed.)

Part 3

Identify the critical value(s) for this test.

enter your response here

(Round to two decimal places as needed. Use a comma to separate answers as needed.)

Part 4

What is the correct conclusion at the

=0.01

level of significance?

Since the test statistic is

less

greater

than the critical value,

do not reject

reject

the null hypothesis. There

is not

is

sufficient evidence at the

=0.01

level of significance to conclude that the fund has moderate risk.