Answer:
C. (n₁ + n₂ - 2) degrees of freedom
Step-by-step explanation:
The t-test for difference between two mean when variance are equal is:

where ,
= Mean of Sample 1
= Mean of Sample 2
s = standard deviation
n_1 = size of Sample 1
n_2 = size of Sample 2
and t is Student's t-test with (n₁ + n₂ - 2) degrees of freedom.
I don’t see a z anywhere in the equation but with the other numbers (I think) is -6.
Answer:
No, she's wrong

Step-by-step explanation:
So starting from the beginning...

Subtract the 3 from both side and it will look like...

Then add 2x from both sides and it will look like...

Finally divide by 5 to both sides and it will look like...

Answer:
i assume you mean divide so its 18308
Step-by-step explanation: