Question

A study was conducted to determine whether the mean braking distance of four-cylinder cars is greater than the mean braking distance of six-cylinder cars. A random sample of 20 four-cylinder cars and a random sample of 20 six-cylinder cars were obtained, and the braking distances were measured.

(a) What would be the appropriate hypothesis test for this analysis? - t-test for two independent samples - t-test for dependent samples - z-test for population mean -correlation

(b) Explain the rationale for your selection in (a). Specifically, why would this be the appropriate statistical approach?

Answer 1

(a) What would be the appropriate hypothesis test for this analysis? - t-test for two independent samples - t-test for dependent samples - z-test for population mean -correlation

Answer: The appropriate hypothesis test for this analysis is the t-test for two independent samples. We are given two independent samples each with sample size 20.

(b) Explain the rationale for your selection in (a). Specifically, why would this be the appropriate statistical approach?

Answer: We use the two sample t-test for two independent samples for population means because given two samples are independent. Also, we are not given population standard deviations for these two samples. If the population standard deviations were given, then we would use the two sample z test for the population means. First sample is given for the breaking distances for four cylinder cars and second sample is given for the breaking distances for six cylinder cars. Also, population standard deviations are not provided for these two samples from which they are selected, so we use two sample t test instead of two sample z test for the population means.