Answer:square root of 25 square root of 4
Step-by-step explanation:
Answer:
See the proof below.
Step-by-step explanation:
For this case we just need to apply properties of expected value. We know that the estimator is given by:

And we want to proof that 
So we can begin with this:

And we can distribute the expected value into the temrs like this:

And we know that the expected value for the estimator of the variance s is
, or in other way
so if we apply this property here we have:

And we know that
so using this we can take common factor like this:

And then we see that the pooled variance is an unbiased estimator for the population variance when we have two population with the same variance.
6 and 30 camd be simplified with 6
the result will be 1:5
so the question mark is 5
Answer:
These are both 20 so that means that this is proportional, yes.
Step-by-step explanation:
Hi.
To figure this out we can do something called cross multiplying to find a cross product. If we do this and our two answers are equal then it is indeed a proportion.
Here is how we do this.

So basically what we are doing is multiplying across in a diagonal direction.
Diagonal meaning like a slash / .
So in this case we would multiply the 4 and the 5 , since they're diagonal from each other.
Do the same for the 2 and the 10.
So we have to multiply :
4 x 5
2 x 10
=
20
These are both 20 so that means that this is proportional, yes.
Hope this helps.
If you have any questions or concerns feel free to message me.