Answer:
a) For this case we can use the definition of weighted average given by:

And if we replace the values given we have:

b) 
c) 
Step-by-step explanation:
Assuming the following question: "One sample has a mean of M=8 and a second sample has a mean of M=16 . The two samples are combined into a single set of scores.
a) What is the mean for the combined set if both of the original samples have n=4 scores
"
For this case we can use the definition of weighted average given by:

And if we replace the values given we have:

b) what is the mean for the combined set if the first sample has n=3 and the second sample has n=5
Using the definition we have:

c) what is the mean for the combined set if the first sample has n=5 and the second sample has n=3
Using the definition we have:

Answer:
No
Step-by-step explanation:
I don' think that Y varies directly like X does because first they're different numbers. Y=1.2 and X=1.6.
Answer: 1.C 2.B 3.C
Step-by-step explanation:
Yes it is 200. If its not 5 or more you round down, in this case 50 or more.
Answer:
the answer is a
Step-by-step explanation:
distribute the minus sign on the second set of parenthesis and combine like terms