1. ## Two Sample T-Test

I have a t-test question that I need help with.

This is the information that has been given to me.

Male Female
m=41 n=17

x(bar) =69.2 y(bar)= 66.7

S(x)=2.66 S(y)= 2.34

Test to see whether the difference between mean male and female is 5.5 inches.
I got the test statistic which was 3.57, and the pooled estimate variance to be 2.57

The problem is i cant get the p value, i dont understand where i am meant to look in the tables.

In my book it says the forumula to get the P-Value is: P=2*P(T>|t|) ,where t is observed value.

Thomas

2. ## Re: Two Sample T-Test

Originally Posted by thomasboateng
I have a t-test question that I need help with.

This is the information that has been given to me.

Male Female
m=41 n=17

x(bar) =69.2 y(bar)= 66.7

S(x)=2.66 S(y)= 2.34

Test to see whether the difference between mean male and female is 5.5 inches.
I got the test statistic which was 3.57, and the pooled estimate variance to be 2.57

The problem is i cant get the p value, i dont understand where i am meant to look in the tables.

In my book it says the forumula to get the P-Value is: P=2*P(T>|t|) ,where t is observed value.

Thomas
What is your test statistic? What are the number of degrees of freedom?

CB

3. ## Re: Two Sample T-Test

I still dont get it,

my test statistic is 3.37. not sure what my degrees of freedom are?

4. ## Re: Two Sample T-Test

Originally Posted by thomasboateng
I still dont get it,

my test statistic is 3.37. not sure what my degrees of freedom are?

CB

5. ## Re: Two Sample T-Test

yes the degrees of freedom is 56 for me

but in the example its 66 and its cv is

If using 2-tailed test

Alpha.05, tcv= 1.997

it just tells me the cv is 1.997 is it always going to be 1.997 ?

Thomas

6. ## Re: Two Sample T-Test

Thomas,

Yes you are correct it is always going to be 1.997 for two sample t tests.

Luke

7. ## Re: Two Sample T-Test

Originally Posted by thomasboateng
yes the degrees of freedom is 56 for me

but in the example its 66 and its cv is

If using 2-tailed test

Alpha.05, tcv= 1.997

it just tells me the cv is 1.997 is it always going to be 1.997 ?

Thomas
No you need to look up the cumulative t-distribution with 56 degrees of freedom for a critical value of 0.975, which will give t_cv=2.004 rather than the t_cv=1.997 for 66 degrees of freedom.

(You may have a table of critical values for t-tailed tests then you would look up the critical value that corresponds to 0.95 probability of the t-score being between +/- t_cv)

CB

8. ## Re: Two Sample T-Test

Originally Posted by lukeheselden
Thomas,

Yes you are correct it is always going to be 1.997 for two sample t tests.

Luke
This is wrong, see my other post.

CB