Using the 68-95-99.7 Rule
Not what you're looking for?
Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantities:
Suggest you make a drawing and label first.
Percentage of scores less than 100
Relative frequency of scores less than 120
Percentage of scores less than 140
Percentage of scores less than 80
Relative frequency of scores less than 60
Percentage of scores greater than 120
Purchase this Solution
Solution Summary
This solution provides the simple calculations to find the required quantities.
Solution Preview
mu = 100, sigma = 20
z = (x - mu)/sigma
(a) x = 100
z = (100 - 100)/20 = 0
Percentage of scores less than 100 = 100 * P(x < 100) = 100 * P(z < 0) = 100 * 0.5 = 50%
(b) x = 120
z = (120 - ...
Purchase this Solution
Free BrainMass Quizzes
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.
Know Your Statistical Concepts
Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.
Measures of Central Tendency
This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.