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? (i) t-test for two independent samples (ii) t-test for dependent samples (iii) z-test for population mean (iv) correlation (b) Explain the rationale for your selection in (a). Specifically, why would this be the appropriate statistical approach?

Answer 1

a)

i) t test for independent samples

b) This would be appropriate statistical approach because we are taking samples of 20 cars. Here therefore the sample size is small that is why we cannot use z test.

Also we are taking two independent samples.

If we were taking two observations on the same sample unit then it would be appropriate to use t test for dependent samples.

Also here we are not checking the relationship between distances due to corresponding cars. We are comparing two means.

Hence t test for independent samples is appropriate statistical approach for goven situation.