Question

In an article in the Journal of Advertising, Weinberger and Spotts compare the use of humor in television ads in the United States and the United Kingdom. They found that a substantially greater percentage of U.K. ads use humor.

(a) Suppose that a random sample of 387 television ads in the United Kingdom reveals that 130 of these ads use humor. Find a point estimate of and a 95 percent confidence interval for the proportion of all U.K. television ads that use humor. (Round your answers to 3 decimal places.)   

pˆp^ =

The 95 percent confidence interval is [,].

(b) Suppose a random sample of 534 television ads in the United States reveals that 114 of these ads use humor. Find a point estimate of and a 95 percent confidence interval for the proportion of all U.S. television ads that use humor. (Round your answers to 3 decimal places.)

pˆp^ =

The 95 percent confidence interval is [,].

(c) Do the confidence intervals you computed in parts a and b suggest that a greater percentage of U.K. ads use humor?

(Click to select)NoYes , the U.K. 95 percent confidence interval is (Click to select)abovenot above the maximum value
in the confidence interval for the U.S.

Answer 1

a)

Sample size = n = 387

x = 130

Point estimate = Sample proportion is

We have to construct a 95% confidence interval for the population proportion.

Formula is

Here E is a margin of error.

Zc = 1.96

( From z table)

So confidence interval is ( 0.3359 - 0.0471 , 0.3359 + 0.0471) => ( 0.2889 , 0.3830)

----------------------------------------------------------------------------------------------------------------------------

b)

Sample size = n = 534

x = 114

Point estimate = Sample proportion is

We have to construct a 95% confidence interval for the population proportion.

Formula is

Here E is a margin of error.

Zc = 1.96

( From z table)

So confidence interval is ( 0.2697 - 0.0376 , 0.2697 + 0.0376) => ( 0.2320 , 0.3073)

------------------------------------------------------------------------------------------------------------------------------

c)

Yes, the U.K. 95% confidence interval is above the maximum value in the confidence interval for the U.S.