Question 58465
1. The mean starting salary for college graduates in the spring of 2004 was $36,280. Assume that the distribution of starting salaries follows the normal distribution with a standard deviation of $3,300. What percent of the graduates have starting salaries: 
1. Between $35,000 and $40,000)

P(35000<x<40000)=P[(35000-36280)/3300 <z<(40000-36280)/3300)=0.52

2. More than $45,000? 
P(x>4500)=P(z>(45000-36280)/3300)=0.004

3. Between $40,000 and $45,000? 
Same procedure as #1; Ans: 0.126


2. The price of shares of Bank of Florida at the end of trading each day for the last year followed the normal distribution. Assume there were 240 trading days in the year. The mean price was $42.00 per share and the standard deviation was $2.25 per share.

1. What percent of the days was the price over $45.00?
Ans: 0.0912
 How many days would you estimate?
0.0912*240=21.89 days 
2. What percent of the days was the price between $38.00 and $40.00?
Ans: 0.149
3. What was the stock's price on the highest 15 percent of days?
Draw the bell curve. Indicate a point above which 15% lies.
Find the z-score corresponding to that point:
Ans: z=1.036
Now, find the x-score corresponding to that z-score.
1.036 = (x-42)/2.25
x=44.33
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Cheers,
Stan H.