- #1
kliker
- 104
- 0
a teacher wants to see if the lab helps the student perform better. He took two independent samples, 77 students who attended the lab and 23 who didnt attend the lab. 6 out of 77 that attended the lab said that they had difficulties, 16 out of 23 that didnt attend the lab said that had difficulties
i need to find the 95% confidence interval for the difference of rates of students that had difficulties
i said p1 = 6/77 = 0.0779
p2 = 16/23 = 0.695
then i said that the confidence interval is
(0.0779-0.695-1.96*sqrt(0.0779(1-0.779)/77+0.695(1-0.695)/23),0.0779-0.695+1.96*sqrt(0.0779(1-0.779)/77+0.695(1-0.695)/23) =
= (-0.807532,-0.426668)
hence we can be 95% sure that the lab helps student to understand better what they re doing
am i correct? I am not sure if i got the results right, I mean the first sample is big >=30 but the second one is smaller, so I am not sure if i took the right equation
which in this case is the following
p1-p2+/-Za/2*sqrt(p1(1-p1)/n+p2(1-p2)/m)
thanks in advance
i need to find the 95% confidence interval for the difference of rates of students that had difficulties
i said p1 = 6/77 = 0.0779
p2 = 16/23 = 0.695
then i said that the confidence interval is
(0.0779-0.695-1.96*sqrt(0.0779(1-0.779)/77+0.695(1-0.695)/23),0.0779-0.695+1.96*sqrt(0.0779(1-0.779)/77+0.695(1-0.695)/23) =
= (-0.807532,-0.426668)
hence we can be 95% sure that the lab helps student to understand better what they re doing
am i correct? I am not sure if i got the results right, I mean the first sample is big >=30 but the second one is smaller, so I am not sure if i took the right equation
which in this case is the following
p1-p2+/-Za/2*sqrt(p1(1-p1)/n+p2(1-p2)/m)
thanks in advance