17 A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study

620

babies were born, and

341

of them were girls. Use the sample data to construct a

99%

confidence interval estimate of the percentage of girls born. Based on the result, does the method appear to be effective?

enter your response here<

p

(Round to three decimal places as needed.)

Does the method appear to be effective?

No,

the proportion of girls

isnot

significantly different from 0.5.

Yes,

the proportion of girls

is

significantly different from 0.5.

18- Refer to the accompanying data display that results from a sample of airport data speeds in Mbps. The results in the screen display are based on a 95% confidence level. Write a statement that correctly interprets the confidence interval.	TInterval
(13.046,22.15) x=17.598 Sx=16.01712719 n=50

Choose the correct answer below.

A.

The limits of 13.05 Mbps and 22.15 Mbps contain the true value of the mean of the population of all data speeds at the airports.

B.

We have 95% confidence that the limits of 13.05 Mbps and 22.15 Mbps contain the true value of the mean of the population of all data speeds at the airports.

C.

The limits of 13.05 Mbps and 22.15 Mbps contain 95% of all of the data speeds at the airports.

D.

We have 95% confidence that the limits of 13.05 Mbps and 22.15 Mbps contain the sample mean of the data speeds at the airports.

21- Claim: Most adults would erase all of their personal information online if they could. A software firm survey of

583

randomly selected adults showed that

63%

of them would erase all of their personal information online if they could. Find the value of the test statistic.

The value of the test statistic is

enter your response here.

(Round to two decimal places as needed.)

22- Claim: The standard deviation of pulse rates of adult males is

lessthan

11

bpm. For a random sample of

126

adult males, the pulse rates have a standard deviation of

10.2

bpm. Find the value of the test statistic.

The value of the test statistic is

enter your response here.

(Round to two decimal places as needed.)

23-

A certain drug is used to treat asthma. In a clinical trial of the drug,

24

of

265

treated subjects experienced headaches (based on data from the manufacturer). The accompanying calculator display shows results from a test of the claim that less than

12%

of treated subjects experienced headaches. Use the normal distribution as an approximation to the binomial distribution and assume a

0.05

significance level to complete parts (a) through (e) below.

1-PropZTest
	prop<0.12
	z=1.474482786
	p=0.0701758246
	p=0.0905660377
	n=265

a. Is the test two-tailed, left-tailed, or right-tailed?

Two-tailed test

Right tailed test

Left-tailed test

b. What is the test statistic?

z=enter your response here

(Round to two decimal places as needed.)

c. What is the P-value?

P-value=enter your response here

(Round to four decimal places as needed.)

d. What is the null hypothesis, and what do you conclude about it?

Identify the null hypothesis.

A.

H0:p=0.12

B.

H0:p<0.12

C.

H0:p>0.12

D.

H0:p0.12

Decide whether to reject the null hypothesis. Choose the correct answer below.

A.

Reject

the null hypothesis because the P-value is

lessthanorequalto

the significance level,

.

B.

Failtoreject

the null hypothesis because the P-value is

greaterthan

the significance level,

.

C.

Reject

the null hypothesis because the P-value is

greaterthan

the significance level,

.

D.

Failtoreject

the null hypothesis because the P-value is

lessthanorequalto

the significance level,

.

e. What is the final conclusion?

A.

There

is

sufficient evidence to warrant rejection of the claim that less than

12%

of treated subjects experienced headaches.

B.

There

isnot

sufficient evidence to support the claim that less than

12%

of treated subjects experienced headaches.