
Example: The scores on a final exam approximate a normal curve
wuth a mean of 71 and standard deviation of 11. What
percentage of the students scored between 70 and 89?
12
71
70 89
Step 1: First, calculate the probability that a student chosen at
random obtained a score greater than 70. (Square the
standard deviation to get the variance.)
(IvrnTl fN^
71(enter!
11 QCZD
70 LITF'N
(nxt!
1: .536217586697
Step 2: Now, do the same calculation for a score of 89, after recalling
the last argument used.
89 UTPN
2= .536217586697
1: 5.08817524756E-2
Step 3: Subtract the two values. About 49% of the students scored
between 70 and 89.
0
1: .485335834221
12-6 Functions of Real and Complex Numbers
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