Maclean's conducted a marketing solutions poll of mutual funds and fund owners. One question asked fund owners

Question:

Maclean's conducted a marketing solutions poll of and fund owners. One question asked fund owners what action they took after the October 1997 market drop. Seventeen percent of respondents said they bought more funds. Consider as unusual any result that differs from the mean by more than two standard deviations. That is, unusual values are either less than σ - 2σ or greater than µ + 2σ.
a. Find the mean and standard deviation of the number of respondents who bought more funds, if groups of 900 fund owners were polled.
b. In one of these polls of 900 fund owners, 140 respondents bought more Is this unusual?
Mutual Funds
Mutual funds are like a pool of funds gathered by different small investors that have simalar investment perspective about returns on their investments. These funds are managed by professional investment managers who act smartly on behalf of the...