df = [[tex](s1^2/n1+s2^2/n2)^2/{1/n1-1 (s1^2/n1)^2+1/n2-1(s2^2/n2)^2}].[/tex]
What does confidence interval mean?
Your estimate's mean plus and minus the range of that estimate's fluctuation is called a confidence interval.
If you repeat your test, you can expect your estimate to fall between these numbers with a reasonable degree of certainty. Another term for probability in statistics is confidence.
The 95%
[tex]c.i=(x1bar-x2bar)-zalpha/2 SE, assuming both n1 and n2 are greater than 30, SE=sqrt[sigma1^2/n1+sigma2^2/n2][/tex]
=(68.72222-66.45833)-1.96 SE
=2.26389-1.96 SE,
The 95%
[tex]c.i=(x1bar-x2bar)-talpha/2 SE, where, SE=sqrt (s1^2/n1+s2^2/n2),[/tex]
and both n1 and n2 are less than 30,
t critical is computed at alpha/2,
and
df= [tex](s1^2/n1+s2^2/n2)^2/{1/n1-1 (s1^2/n1)^2+1/n2-1(s2^2/n2)^2}].[/tex]
Learn more about confidence interval
brainly.com/question/24131141
#SPJ4
