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# Probability

A poll of 1,250 investors conducted, assume that 50% of the investors found the market less attractive to the prior years. P=.5, find the probability that the sample proportion obtained from the sample of 1,250 investors would be:
A. within 4% points of the population, that is P(.46<^p<.54).
B. within 2% points of the population proportion

#### Solution Preview

Let p^ denote the sample proportion obtained from the sample of 1,250 investors. Then we know that p^ follows roughly normal distribution (by the large number law) with mean p=0.5 and standard deviation sigma=square root of p(1-p)/n =0.0141.

(A) The probability ...

#### Solution Summary

The solution discusses A poll of 1,250 investors conducted, assume that 50% of the investors found the market less attractive to the prior years. P=.5, find the probability that the sample proportion obtained from the sample of 1,250 investors would be:
A. within 4% points of the population, that is P(.46<^p<.54).
B. within 2% points of the population proportion

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