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Need Help for math Test tommorrow!!!!!!!!!!
- Thread starter ahadkhan
- Start date
How do you calculate the mean?So is this statement true or false:
A random sample of 100 people had a mean income of $35,000, Therefore a random sample of 200 people would have a mean income of $70,000.
What does the mean of a sample estimate?
Absolutely correct.you calculate it by finding the sum then dividing by the total numbers in the set!
When dealing with a sample, there are TWO sets to keep in mind. One is frequently called the population; it might be all the cars in the US.
The other set is the sample, which might be a set of some of the cars in the population. In the language of sets, the sample is a subset of the population. The idea is that, with a large enough randomly selected sample, information about the population as a whole can be estimated with good reliability from information about the sample.
So, how was the mean income of the FIRST sample calculated? You basically already answered this question.
Now, in all probability, the mean income of the population is approximately equal to the mean from the first sample.
So would you expect the mean of the second sample to be greatly different?
But wait, we now have the income of 200 people from a second sample. That will almost certainly be necessarily more than the income of just 100 people. So how can the means of the two samples be about the same?
HallsofIvy
Elite Member
- Joined
- Jan 27, 2012
- Messages
- 7,763
Certainly, you would expect the sum of 200 people's salaries to be about twice the sum of 100 people's salaries. But then what happens?you calculate it by finding the sum
then dividing by the total numbers in the set!