sampling statistic Problem

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cseverino

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Apr 22, 2019
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Hello there, I was just wondering if someone could help me on these problem
Now that she has some descriptive information on her sample, your colleague wants to discover how well her sample represents the population from which it was selected. She tells you that the population size was 500 and that she used probability sampling procedures to select and survey 50 people.

1. What would have happened if she had selected a different sample of 50 people? What would have changed.


2. Will she be able to use her sample statistic to estimate the true population parameter? Why or why not?
3. Will she be able to use her sample statistic to state with 100% accuracy the actual population parameter? Why or why not? Thanks
 
We probably need to see the whole question to help with this one. What came before this and what have you done so far/what are you thoughts?
 
Harry_the_cat said:
We probably need to see the whole question to help with this one. What came before this and what have you done so far/what are you thoughts?
Click to expand...
Hi Harry, thank you so much for replaying my post. This is 2nd part of a research problem that am working on. the answers bellow are what I needed to continue on the second part.
Years of education:
Mean = 13.52 years
Standard deviation = 2.50 years
Number of people arrested:
Mean = 2.12 people
Standard deviation = 2.48 people

Here is the Question page.
Again thank you
 

Attachments

  • 352 - Problem Set, Part Two(2).pdf
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Ok we need that info.
Firstly, what are your thoughts on the questions? Then we can guide you.
 
Harry_the_cat said:
Ok we need that info.
Firstly, what are your thoughts on the questions? Then we can guide you.
Click to expand...
The only thing that comes to mind, is that apparently it will no have any changes because I assumed that she will another sample from the same population size of the 500. Or the Population size will be less !
Thank you.
 
Would you expect the mean to be exactly the same if you took a different sample of 50 from the same population?
What about the s.d?
 
Harry_the_cat said:
Would you expect the mean to be exactly the same if you took a different sample of 50 from the same population?
What about the s.d?
Click to expand...
To be honest, I do not know but if is taking from the same population, would be using the same mean and the sd !
 
Ok. Imagine this.

There are 500 people in the room.

You take a random sample of 50 people and measure their heights. You calculate the mean and standard deviation of these 50 heights. Let's say the mean of these 50 heights is 170.4 cm and the standard deviation of these 50 heights is 4.92cm.

Then you select a different random sample of 50 people and do the same thing.

Do you expect the mean and standard deviation calculated from these 50 heights to be exactly the same as the mean and sd calculated from the first 50 heights?
 
No, because if you take your example "Let's say the mean of these 50 heights is 170.4 cm and the standard deviation of these 50 heights is 4.92cm." if we take another sample from the population mean, it will have different results.( 50 wights is # and the SD=# So I think what you are trying to teach me is that, even that they are from the same population side, their outcomes will np me the same. so I will go base on that !
 
Correct. The mean and sd will probably be close (if the sample is random) but most unlikely to be exactly the same.
 
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