A random sample of 20 customers who drive luxury cars showed that their average distance driven between oil changes was 3187 miles with a sample standard deviation of 42.50 miles. Another sample of 10 customers who drive compact lower-price cars resulted in an average distance of 3214 miles with a sample standard deviation of 50.70 miles. Suppose that the standard deviations for the two populations are not equal. Using the 5% significance level, can you conclude that the mean distance between oil changes is lower for all luxury cars than for all compact lower-price cars?
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Use same process shown in previous post.
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