+118677 I've spent ages trying to work out what this information is telling me.
I don't understand the margin of error so I have ignored it. :/
I think this is what I am being told.
There were 3 samples of 40 people where 25 of the 40 were unhappy with the government.
There were 6 samples of 40 people where 26 of the 40 were unhappy with the government.
etc
You are not really being asked for the sample mean. I think that the wording of the question is really poor because you are given the sample means for each of the 40 samples.
What they really want you to find is the mean of the sample means.
Now there are 3 sample 25 dissatisfied people. that is a total of 3*25=75 dissatisfied people in this 3 samples.
There are 6 samples with 26 dissatisfied people that is a total of 6*26=75 dissatisfied people in this 6 samples.
If you keep going like this you get a total of 2981 dissatisfied people in the 100 samples.
So the average number of dissatisfied people per sample is 2981/100 = 29.81 people
The percentage of dissatisfied people in these samples is 29.81people per 40 person sample.
\(\mbox{The percentage of dissatisfied people } =\frac{29.81}{40}*100\%=\frac{2981}{40}\%=74.52\%\)
So I believe that the last one is the answer. 
If you have questions about what I have done, please ask
liberal arts math
