Thread: Hypothesis Testing

Hi guys, I need some help with this one ( mainly "1" and "2" ):

A research check tails of 40 cats. these are the results:


average s.d n
Males 190 15 22

Famales 180 12 18

1. check the hypothesis that the tails of the males are longer, with significant level of 10%.

2. what is the significant of the result ? ( p value )

3. build a confidence interval of 90% to the mean difference

Originally Posted by weeg

average s.d n
males 190 15 22

famales 180 12 18

3. Build a confidence interval of 90% to the mean difference

You should be pooling the two sample variances if you're using 40-2 degrees of freedom.
That means you are assuming equal varainces.
Otherwise if you use the above standard deviation you need Satherwaithe's approximation for the degrees of freedom.
I would do a one sided test where Ha is the claim that the male's tail is longer on average.

My changes...