Last year, those who took the LSAT test a second time score an average of 2.8...

Last year, those who took the LSAT test a second time score an average of 2.8 points higher than the first time. Suppose two independent and identically distributed random samples are drawn from this year’s exam: first-time and second-time LSAT takers.

a) Write the hypothesis test where the null is that the difference in scores between first- and second-time LSAT takers has not changed since last year and a two-sided alternative.
b) Suppose two independent random samples are drawn. One random sample contains the LSAT scores of first-time takers and has 25 observations and a sample variance of 256. The other random sample contains the LSAT scores of second-time takers and has 16 observations and a sample variance of 144. Derive the rejection rule at ! = 0.20 of the test in part a).

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orchestra answered 2 years ago

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