Answer:
maybe -9.1666 top second one?
Answer:
The combined standard deviation is 1.58114.
Step-by-step explanation:
The formula to compute the combined standard deviations of two different data sets is:

Here
is the combined mean given by:

It is provided that the sample size is same for both the data sets, i.e.
Compute the combined mean as follows:

Compute the combined standard deviation as follows:

Thus, the combined standard deviation is 1.58114.
Answer:
(-13, -4)
Step-by-step explanation:
It is about as easy to try the solutions as it is to find them from scratch.
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However, we can determine which one it is by adding twice the second equation to the first.
(-2a +3b) +2(a -4b) = (14) +2(3)
-5b = 20
b = -4 . . . . . . matches the first choice
You will have a 3:6 probability of getting an even number