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.
Do you need to switch it around or do something else?
Answer:
7/10, 14/20, 21/30, 28/40, 35/50, 42/60, 49/70, 56/80, 63/90, 70/100, 77/110, 84/120, 91/130, 98/140, 105/150, 112/160, 119/170, 126/180, 133/190, 140/200,
Step-by-step explanation:
Answer:
-5
Step-by-step explanation:
Geometric sequences have common ratios.
You can see if a sequence is geometric by computing:
.
If you get the same result per consecutive pair, then there is a common ratio and the sequence is geometric.
Let's see:

So if this equations holds (if all 3 fractions equal the same thing), then is geometric and we have also have computed the common ratio.
The first fraction results in -250/50=-5.
The second fraction results in 50/-10=-5.
The third fraction results in -10/2=-5.
All three fractions are equal and so the equation holds so it is geometric and the common ratio is -5.
Answer:
Step-by-step explanation:
h(-1) = - 3|3(-1) - 6| - 3
h(-1) = - 3|-3 - 6| - 3
h(-1) = - 3|-9| - 3
h(-1) = - 3(9) - 3
h(-1) = - 27 - 3
h(-1) = - 30