Questions
1. A normal distribution has a mean of 30 and a standard deviation of 3.5. Find
a.) P(23<x<30)
b.) P(32<x<37)
c.) P(x<23)
d.) P(22<x<26.5)
e.) P(x>39.8)
f.) P(x>20.2)
In questions 2 and 3 assume that IQ scores are normally distributed with a mean of 100 and a standard deviation of 15.
2. If some one is selected at random, find the
probability that he or she has an IQ between 90 and 115.
3. If some one is randomly selected, find the probability that he or
she has an IQ above 130.
In questions 4 and 5 assume that students between
the ages of 15 and 18 spend an average of $45.34 each month. Further assume the amounts
are normally distributed with a standard deviation of $9.18 per month.
4. If a person in the age group cited is randomly
selected, find the probability that she or he spends at most $68.29 per month.
5. If a person in the age group from 15 to 18 is randomly selected,
find the probability that she or he spends between $22.39 and $31.57 each month.