Note :- If sample size n > 30 OR Population standard deviation σ is given then We use Z test.
If sample size n < 30 AND Population standard deviation σ is unknown then we use t test.
In this question we are not given Population standard deviations σ1 and σ2.
Also n1 = 14 and n2 = 13 both sample sizes are LESS than 30.
Therefore we use t test.
Given :- Assume the population standard deviations are equal. ( σ1 = σ2)
then Degrees of freedom = n1 + n2 - 2 = 14 + 13 - 2 = 25.
(kindly find the image attached with this solution)
Answer :- Therefore 25 degrees of freedom are used to find the t critical value.
<span>The integral of (x^2 + 6x)dx is 1/3x^3 + 3x^2 + c.
Because this is not an integration with specific bounds, you must include a constant at the end.
In general, to integrate, add 1 to the exponent of x and then whatever number is the exponent of x, divided the number in front of x by that.</span>
5/13t= -9
Then t =( -9*13) / 5
T=-23.4
Hey make 200 per hour, and would need 63 hours to make 12600 shirts. 63/9=7
They’d need to work for 7 days
Hope this helps