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Of the 98 teachers who responded, 23.5%said that they had one or more tattoos.

(a) Construct and interpret a 95%confidence interval for the actual proportion of teachers at the AP institute who would say they had tattoos.

(b) Does the interval in part (a) provide convincing evidence that the proportion of teachers at the institute with tattoos is not 0.14(the value cited in the Harris Poll report)? Justify your answer.

(c) Two of the selected teachers refused to respond to the survey. If both of these teachers had responded, could your answer to part (b) have changed? Justify your answer

Short Answer

Expert verified

(a) We are 95%confident that the true population proportion is between 0.151and 0.319.

(b) Yes, there is sufficient evidence to support the claim.

(c) It is noted that the conclusion does not change when the response of the two teachers is included

Step by step solution

01

Part (a) Step 1: Given information

Given in the question that, of the 98teachers who responded, 23.5%said that they had one or more tattoos.

02

Part (a) Step 2: Explanation

According to the information, we observed that

n=98

p^=23.5%=0.235

For confidence level, 1-=0.95, determine, z/2=z0.025

z/2=1.96

The margin of error is

localid="1650685513171" E=z/2p^(1-p^)n=1.960.235(1-0.235)980.084

The confidence interval is

localid="1650685516522" 0.151=0.235-0.084=p^-E<p<p^+E=0.235+0.084=0.319

03

Part (b) Step 1: Given information

Of the 98teachers who responded, 23.5%said that they had one or more tattoos.

04

Part (b) Step 2: Explanation

We have to find the hypothesis

H0:p=0.14

H0:p0.14

Determine the value of the test-statistic:

localid="1650685524452" z=p^-p0p01-p0n=0.235-0.140.14(1-0.14)982.71

The localid="1650685529133" P-value is the chance of getting the test statistic's result, or a number that is more severe. Calculate the localid="1650685533236" P-value in table localid="1650685536989" Aas follows:

localid="1650685554330" P=P(Z<-2.71orZ>2.71)=2P(Z<-2.71)=20.0034=0.0068

Reject the null hypothesis if the P-value is less than the significance level:

P<0.05RejectH0

05

Part (c) Step 1: Given information

Of the 98teachers who responded, 23.5%said that they had one or more tattoos.

06

Part (c) Step 2: Explanation

From the given values

The sample proportion is calculated by dividing the number of successes by the sample size:

If both professors indicated they had one or more tattoos, the following would happen:

p^=xn=23.5%98+210025100=0.25

If both teachers indicated they didn't have any tattoos, then:

p^=xn=23.5%98+010023100=0.23

Let's determine the hypothesis

H0:p=0.14

H0:p0.14

Compute the test statistic's value:

localid="1650685575009" P=P(Z<-3.17orZ>3.17)=2P(Z<-3.17)=20.0008=0.0016

localid="1650685581138" P=P(Z<-2.59orZ>2.59)=2P(Z<-2.59)=20.0048=0.0096

Reject the null hypothesis if thelocalid="1650685612366" P-value is less than the significance level.

P<0.05RejectH0

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