Q2. A state that requires periodic emission tests of cars operates two emissions test stations, A...

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Q2. A state that requires periodic emission tests of cars operates two emissions test stations, A and B, in one of its towns. Car owners have complained of lack of uniformity of procedures at the two stations, resulting in different failure rates. A sample of 400 cars at Station A showed that 53 of those failed the test; a sample of 470 cars at Station B found that 51 of those failed the test. (a) What is the point estimate of the difference between the two population proportions? (b) Construct a 98% confidence interval for the difference between the two population proportions. (c) Testing at the 5% significance level, can you conclude that the two population proportions are different? Use the p-value approach. Q2. A state that requires periodic emission tests of cars operates two emissions test stations, A and B, in one of its towns. Car owners have complained of lack of uniformity of procedures at the two stations, resulting in different failure rates. A sample of 400 cars at Station A showed that 53 of those failed the test; a sample of 470 cars at Station B found that 51 of those failed the test. (a) What is the point estimate of the difference between the two population proportions? (b) Construct a 98% confidence interval for the difference between the two population proportions. (c) Testing at the 5% significance level, can you conclude that the two population proportions are different? Use the p-value approach.