Download Lesson 7 - Coweta County Schools

Notes Over 12.7
Using a Normal Distribution
Area Under a Curve
.34 .34
.0235
.135
.0015
.0235
.135
.0015
Notes Over 12.7
Using a Normal Distribution
A normal distribution has a mean of 80 and a standard
deviation of 7. Find the probability that a randomly
selected x-value is in the given interval.
1. between 66 and 87
0.135  0.34  0.34
 0.815
.34 .34
.0235
.135
59 66
.0015
.0235
.135
73 80 87 94101
.0015
Notes Over 12.7
Using a Normal Distribution
A normal distribution has a mean of 80 and a standard
deviation of 7. Find the probability that a randomly
selected x-value is in the given interval.
2. at most 94
0.50  0.34  0.135
 0.975
.34 .34
.0235
.135
59 66
.0015
.0235
.135
73 80 87 94101
.0015
Notes Over 12.7
Using a Normal Distribution
2. The waiting time for drive through customers at a
certain bank during the busiest hours is normally
distributed with a mean of 8 minutes and a standard
deviation of 2 minutes. What is the probability that the
next two customers will wait longer than 8 minutes?
0.5  0.5  0.25
.34 .34
.0235
.135
.0235
.135
2
.0015
.0015 4 6 8 10 12 14
Notes Over 12.7
Finding a Binomial Probability
A scientist claims that 18% of all patients with high
blood pressure have negative side effects from a
certain kind of medicine. There are 120 patients in a
random study.
4. What is the probability that you will find at most
30 patients with negative side effects?
x  np  120 0.18  22
  np1  p   21.60.82  4
0.50  0.34  0.135
.34 .34
.0235
.135
.0235
.135
10
26
18
30
34
22
14
.0015
.0015
 0.975
Notes Over 12.7
Finding a Binomial Probability
A scientist claims that 18% of all patients with high
blood pressure have negative side effects from a
certain kind of medicine. There are 120 patients in a
random study.
5. What is the probability that you will find at least
18 patients with negative side effects?
0.50  0.34
 0.84
.34 .34
.0235
.135
.0235
.135
10
26
18
30
34
22
14
.0015
.0015
Notes Over 12.7