Probability
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The z score that corresponds to a data value
represents a Normal Percentile.
These percentiles can be found on the table
on pages A-29 and 30 in the back of your
book.
These percentiles represent the probability of
being at that z score or lower. Cumulative
area from the left.
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Determine the area under the normal curve to
the left of z=1.00
Determine the area under the normal curve
between z=-1.5 and z=1.0
pg 876-880 #3, 4, 6, 8
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Male heights are distributed with a mean of
69 inches and a standard deviation of 2.5
inches.
Female heights are normally distributed with
a mean of 64.5 inches and a standard
deviation of 2.5 inches.
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pgs 890-892 #4-12
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Label the graph for you, find your z-score
and percentile!
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The blood pressure of an 18 year old woman
is normally distributed with mean of 120 and
a standard deviation of 12. Draw and label
the Normal Model for this data.
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What percent of 18 year old women have a
blood pressure between 96 and 144?
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Greater than 120?
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Less than 96?
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The normal car speeds on an old town
highway have a mean of 77 and a standard
deviation of 9.1. What is the value of the 85th
percentile?
◦ Step 1: Look up the closest to .85 (%) on the ztable.
◦ Step 2: Find the corresponding z-score.
◦ Step 3: Set up an equation with the z-score, mean,
𝑥−𝜇
and standard deviation. 𝑧 =
𝜎
◦ Step 4: Solve for x.