stats: find estimators; 2-sided 90% conf. int for mu1, mu2;

mathdweeb

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Jul 2, 2008
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ok so i got this stats problem that is turning out to be a big problem. it reads as follows :

assume that 6,14,8,12,14,11,10,10,8 and 14,10,9,11,15,15,10,13,14 are two independent samples from normal distributions N(µ,?2[sup:1victy6i]1[sub:1victy6i][/sub:1victy6i][/sup:1victy6i] and N(µ,?[sub:1victy6i]2[/sub:1victy6i][sup:1victy6i]2[/sup:1victy6i] respectively

a. determine the estimators for the expectations for the expectations and variance
b. find two sided 90% confidence intervals for the parameters µ[sub:1victy6i]1[/sub:1victy6i] and µ[sub:1victy6i]2[/sub:1victy6i]
c. find two sided 90% confidence intervals for the parameters ?2[sup:1victy6i]1[sub:1victy6i][/sub:1victy6i][/sup:1victy6i] and ?[sub:1victy6i]2[/sub:1victy6i][sup:1victy6i]2[/sup:1victy6i]
d. Give the appropriate answer with significance level 90% and under the assumption ?[sub:1victy6i]1[/sub:1victy6i] = ?[sub:1victy6i]2[/sub:1victy6i] to the question is µ[sub:1victy6i]1[/sub:1victy6i]=µ[sub:1victy6i]2[/sub:1victy6i]

ok so far I have been able to part a properly and i got an estimated mean of 10.33 for the first set of data and 12.33 for the second set of data i calculated the variance for the first set of data as 7.5 and 5.5 for the second set of data... this was after a lot of calculations :D

Im having problems with part (b) and (c) i used the estimator formula and I think somewhere somehow I messed it up, im also having problems finding the explicit values :? i know im supposed to use the tables but yeah its confusing me big time when i don't know wats wat...
i desperately need direction asap... please
cheers for any help in advance
 
Use the T-distribution for b. and the \(\displaystyle \chi^2\)-distribution for c.
 
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