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Proportion of Samples

  • Thread starter Changoo
  • Start date
7
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I hope someone can tell me where I am going wrong with this dang homework problem. There are several questions to this one problem, but once I figure this out, I will be able to figure the other parts of this question out.


Approximately 5% of US Families have a net worth in excess of 1 million. A survery in the year 2000 found that 30 percent of Ford's employees were millionaires. If random samples of 100 Ford's employees had been taken that year what proportion of the samples would have been between 25% and 35%?

Here I go:

100(.30)=30
100(1-.30)=70

thus, .25-.30/(square root of) (.30)(.70)/100=-.05/.0458=-1.092

Z=.1379

and

.35-.30/.0458=1.092

Z=.8621


I am lost here. Can someone help??
 

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