Students On Diets
By calvinw
Here is problem involving sample proportions. This one is about dieting.
Make sure when you are doing these problems that you draw the curves that go with the information. It is much easier to understand what you are doing if you draw the curves and areas.
In all the problems using the sampling distribution you want to compute areas in some original distribution (the 
-distribution in this case) and you do that by changing things into z-scores and computing the areas under a standard normal curve instead:
The 
is the population proportion and it corresponds to z = 0
The 
is the sample proportion and it corresponds to a value in the left graph above. You change it into a z-value in the right graph above by using the formula for the z-score:
where the stddev is given in this case by:
Problem adapted from Moore’s Basic Practice of Statistics
This entry was posted on April 13, 2007 at 12:35 pm and is filed under Module 5 Examples, Sample Proportions. You can follow any responses to this entry through the RSS 2.0 feed.
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