homework help!

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homework help!
Message posted by Amy (via 63.26.161.146) on October 8, 2001 at 5:32 PM (ET)

I'm having trouble in statistics. I problem that I can't answer is: I have a mean yearly return of about 12%, with a standard deviation of about 16.5%. I need to find what range the middle 95% of all yearly returns lie. B)WHAt % of years is the market down(market down for a yearand index is less than zero) C)what % of years does index gain 25% or more?

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Re: homework help!
Message posted by Jack Tomsky (via 208.249.113.130) on October 9, 2001 at 2:04 PM (ET)

In the past, I have looked at 129 years of history of the stock market averages and have found that the year-to-year percentage change follows a bell-shaped curve, easily passing all the standard normality tests. So we can assume that the returns are normally distributed.

A) 12 +/- (1.96)*(16.5)
B) 100*Phi (-12/16.5)
C) 100*Phi((12-25)/16.5)

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