Percentile
Z-Score
Mean/Standard Deviation
Normal Table
68-95-99.7 Rule
100
You are told that your score on an exam is at the 85th percentile of the distribution of scores. This means that...
Your score was equal to or higher than approximately 85% of the people who took this exam.
100
The mean is 80 and the standard deviation is 10. What is the standard score (z-score) for an observation of 90?
1.0
100
The distribution of scores on an SAT exam is Normal, with mean 500 and standard deviation 100. So the median score on the exam is...
500
100
To the nearest tenth, the percentage of scores in a standard Normal distribution that are below z=-1.4 is...
8.1%
100
For a Normal distribution with mean 20 and standard deviation 5, approximately what percent of the observations will be between 5 and 35?
99.7%
200
Here is a list of exam scores for Mr. William's calculus class:
60 61 61 65 72 75 75 78 81 81 85 89 91 98
What is the percentile of the person whose score was 85?
79%
200
Samir earned an 88 on a test for which the class mean was 78 and the standard deviation was 8. Samir's standardized score (z-score) was...
1.25
200
What is the mean of this Normal distribution?
52
200
To the nearest tenth, the percentage of scores in a standard Normal distribution that are between -2.1 and 0 is...
48.2%
200
For a Normal distribution with mean 20 and standard deviation 5, approximately what percent of the observations will be less then 20?
50%
300
Here is a list of exam scores for Mr. William's calculus class:
60 61 61 65 72 75 75 78 81 81 85 89 91 98
What is the percentile of the person whose score was 75?
50%
300
The mean height of African-American men is 69.5 inches and the standard deviation is 2 inches. President Barack Obama is 73.5 inches tall. The standard score (z-score) for his height is...
2
300
What is the standard deviation of this Normal distribution?
6
300
To the nearest tenth, the percentage of scores in a standard Normal distribution that are between -2.1 and 1.1 is...
84.6%
300
For a Normal distribution with mean 20 and standard deviation 5, approximately what percent of the observations will be less than 10?
2.5%
400
What is the definition of percentile?
The percent of observations that are equal to or lower than a particular observation.
400
The distribution of heights of adult of adult men is approximately Normal with mean 69 inches and standard deviation 2.5 inches. How tall is a man whose standardized height is -0.3?
68.25
400
What is the mean of this Normal distribution?
75
400
What is the z-score at the 62nd percentile of a standard Normal distribution?
0.31
400
The distribution of heights of adult men is approximately Normal with mean 69 inches and standard deviation 2.5 inches. What percent of all men are between 66.5 and 71.5 inches tall?
68%
500
What does it mean if you scored within the 25th percentile on a test?
You scored the same or better than 25% of people who took the test.
500
What is the equation for z-score?
z=(x-mean)/standard deviation
500
What is the mean and standard deviation of a standard Normal distribution?
mean=0
standard deviation=1
500
The percentage of observations from a Normal distribution that lie between the standard scores z=-1 and z=2 is closest to...
81.5%
500
What percent of observations fall within 3 standard deviations of the mean?
99.7%