Download Normal distribution - The Oakwood School

Warm Up
If there are 2000 students total in the school, what
percentage of the students are in each region?
50 270
680
680
270 50
Distribution Shapes
Normal Distribution
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Most common distribution in statistics
Many real-life data sets follow this pattern
Examples: SAT scores, heights of people, IQ tests
Also known as a bell curve
Normal Distribution: COPY THIS!
2.5% 13.5% 34%
34% 13.5% 2.5%
Example 1
Suppose that the average blood pressures of patients
in a hospital follow a normal distribution with a
mean of 108 and a standard deviation of 14.
Set up a normal distribution curve.
Example 1
a) What percentage of patients have a blood pressure
of 94 or higher?
b) What percentage of patients have a blood pressure
between 80 and 122?
c) What percentage of patients have a blood
pressure of less that 80?
Example 2
The duration of routine operations in a certain
hospital has approximately a normal distribution
with an average of 125 minutes and a standard
deviation of 18 minutes.
Set up a normal distribution curve.
Example 2
a) What percentage of operations last at least 125
minutes?
b) What percentage of operations lasted between 107
and 143 minutes?
c) What percentage of operations lasted between 89
and 125 minutes?
Example 3
The mean weight of 850 college students is 70 kg and
the standard deviation of 3 kg.
Set up a normal distribution curve.
Example 3
Determine how many students weigh:
a) Between 64 kg and 73 kg.
b) More than 76 kg.
c) Less than 67 kg.
d) Between 70 kg and 76 kg.