Z scores
X values
Area under the curve
Know Your Facts
100
Area to the left of z = 1.32
What is .9066
100
A normal model has a mean = 230 and a standard deviation = 15. Find the following: P(x < 210)
What is 0.0918
100

Find the z score that corresponds to the 95th percentile.

1.64

100
The mean of a z-score distribution is always __________, and the standard deviation is always __________.
What is 0 and 1
200
Area to the right z = -0.63
What is .7357
200
A normal model has a mean = 135 and a standard deviation = 10.4. Find the following : P(x > 146)
What is 0.1446
200
Find the z score that has 78.5% of the distribution's area to its right.
What is -0.79
200
Alicia scored a 70 on her psychology quiz, but the class as a whole averaged a 40. If the standard deviation was 10, what was Alicia’s z-score??
What is 3
300
P(-2.46 < z < 1.75)
What is 0.953
300
A normal model has a mean = 86 and a standard deviation = 5. Find the following: P(85 < x < 95)
What is 0.5434
300
Find the z score for which 80% of the distribution's area lies between -z and z.
What is -1.28 and 1.28
300
The name of the Rule that states the percentages from the mean for 1, 2 and 3 standard deviations
What is the Empirical Rule
400
Find the area for P(z < .46) or P(z > 2.85)
What is 0.6794
400
A normal distribution has a mean = 17.1 and a standard deviation = 4. What x value represents cuttoff for the bottom 10%?
What is 11.98
400
A normal distribution has a mean = 127 and a standard deviation = 23.5. Find the x value that would correspond to the top 30%.
What is 139.22
400

The 50th percentile of a Normal curve will always correspond to this aspect of the data set.

The mean

500
Find the area under the curve that lies within one standard deviation from the mean.
What is .6826
500
A normal model has a mean = 11.4 and a standard deviation = 3. Find the x value that represents the values above the top 10%?
What is 15.24
500

The heights of mature oak trees are Normally distributed with a mean of 108 inches and a standard deviation of 20 inches. If the oak tree in Kaitlyn's backyard is 150 inches tall, to what percentile does it correspond?

98th

500
The percentage of data that lies under the normal curve
What is 100%
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