Using the output of Exercise 10.18, perform a formal test of the null hypothesis of equal...

Using the output of Exercise 10.18, perform a formal test of the null hypothesis of equal populations. Use α = .05.

Exercise 10.18

The media selection manager for an advertising agency inserts the same advertisement for a client bank in two magazines, similarly placed in each. One month later, a market research study finds that 226 of 473 readers of the first magazine are aware of the banking services offered in the ad, as are 165 of 439 readers of the second magazine (readers of both magazines are excluded). The following Minitab output was based on the appropriate number of 1s and Os as data :

a. Calculate by hand a 95% confidence interval for the difference of proportions of readers who are aware of the advertised services. Compare your answer to the interval given by Minitab.

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b. Are the sample sizes adequate to use the normal approximation?

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c. Does the confidence interval indicate that there is a statistically significant difference using α = .05?