I kept getting the answers that are entered there but that isn\'t right. I\'m no
ID: 3315936 • Letter: I
Question
I kept getting the answers that are entered there but that isn't right. I'm not sure what's wrong.
C Search Textboak Sclutc X New Tab u/webwork2/Principles Stats Wijesurya Fall2017/HW 10/11 Results for this submission Answer Preview Result Entered (-24.8752.-17.5248) (-24. 752,-17.5248) The answer above is NOT correct (1 point) Two random samples are selected trom two independent populations A summary of the samples sizes, sample means, and sample standard deviations is given below n 43, 56.5, 5.1 n,-42, z2-77.7, s 10.1 12 of tre means Iron a aces assuming equal Find a 965% confidence interval for lhe diference m Confidence Interval = | (-24.8752-17 5248) Preview My Answers Submit Answers Your score was recorded You have attempted this problem 20 times You received a score r 0% forthis attempt Your overall recorded score is You have unlimited attempts remaining Emal instructor chExplanation / Answer
Difference in means = 56.5 - 77.7 = -21.2
Standard error (SE) of the sampling distribution.
SE = sqrt[ (s12/n1) + (s22/n2) ]
SE = sqrt[ (5.12/43) + (10.12/42) ] = 1.74175
The degrees of freedom (DF) is:
DF = (s12/n1 + s22/n2)2 / { [ (s12 / n1)2 / (n1 - 1) ] + [ (s22 / n2)2 / (n2 - 1) ] }
DF = (5.12/43 + 10.12/42)2 / { [ (5.12 / 43)2 / (43 - 1) ] + [ (10.12 / 42)2 / (42 - 1) ] }
= 60 (Rounded to nearest integer)
t statistic at 96.5% confidence interval and DF = 60 is 2.157
Margin of error = 1.74175 * 2.157 = 3.757
96.5% confidence interval is,
(-21.2 - 3.757, -21.2 + 3.757)
(-24.957, -17.443)