Stat 133 HW 9 (10 pts)
Name___________________ Group # _____
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Suppose prices (X) of a certain type of stock have a normal distribution with mean 100 dollars and
standard deviation 30 dollars. DRAW PICTURES AN SHOW ALL WORK FOR CREDIT.
INCLUDE UNITS~
1.
______100 dollar________ is the median of these stock prices.
Normal distribution is symmetric
mean=median
2.
______62.93________% of the stock prices are above $90.
P(X>90)=P(Z>(90100)/30)=1P(Z<0.33)=10.3707=0.6293
3.
25% of the stock prices are below _____79.9 dollar __________.
P(X<??)=0.25
Z=0.67
So X=Z*σ+u=0.67*30+100=79.9 dollar
4.
The cutoff point for the highest 10% of the stock prices is 138.4 dollar
_____________.
The highest 10% means we want 90
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 Fall '07
 rumseyjohnson
 Normal Distribution, Standard Deviation, Mean

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