Answer:
A. No, this is not a valid inference because he asked only 20 families
Step-by-step explanation:
You cannot assume that those are the only families that would want to go; you have to ask all the families.
Answer:
The mean for the combined sample = 6.
Step-by-step explanation:
We have been given that one sample of n = 10 scores has a mean of M = 8.
So the sum of 10 scores for 1st sample will be: 
We are also told that second sample of n = 5 scores has a mean of M = 2.
So the sum of 5 scores for 2nd sample will be: 
When the both samples are combined, so total points will be:
and total scores will be
.



Therefore, the mean for the combined sample will be 6.
Your answer to this question is definitely C!
It is multiplied by to because the raidouis is double.