A study was done on skull sizes of humans during different time periods. The results are shown in the table. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below.
Use a 0.050.05 significance level, and test the claim that the mean skull breadth in 4000 B.C is less than the mean skull breadth in A.D 150.
4000 B.C
u1
n=30
x bar =130.94mm
s=5.49 mn
AD 150
u2
n=30
x bar= 135.23
s= 5.41mn
null is u1=u2
ater is u1<u2
t= -3.05
p-value .002
I am having a problem figuring out the confidence interval. I do not what i am doing wrong.
1 answer