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sample of students who look the SAT twice found 427 who were coached and 2733 wh

ID: 3300327 • Letter: S

Question

sample of students who look the SAT twice found 427 who were coached and 2733 who were uncoached. Starting with their verbal scores on the first and second tries, we have these summary statistics: Use Table C to estimate a 99% confidence interval for the mean gain of all students who are coached. 21.545 to 36.355 at 99% confidence. Now test the hypothesis that the score gain for coached students is greater than the score gain for uncoached students. Let mu_1 be the score gain for all coached students. Let mu_2 be the score gain for uncoached students. (a) Give the alternative hypothesis: mu_1 - mu_2 > 0. (b) Give the t test statistic: 2.6459 (c) Give the appropriate critical value for alpha =5%: 2.577. The conclusion is A. There is not sufficient evidence to support the claim that with coaching, the mean increase in scores is greater than without coaching. B. There is sufficient evidence to support the claim that with coaching, the mean increase in scores is greater than without coaching.

Explanation / Answer

here the tail is one tailed and under one tail it is categorised to rigt tailed

and use the excel formulae, ROUND(NORMINV(1-0.05,0,1),2) to get the Z table value is +1.645