SME
Grade 11 Math
Normal distributions, z-scores and margin of error
The main lesson, then each kind of problem it solves.
Normal distributions, z-scores and margin of error
Main lesson
The share between two values
Use this for “Scores have μ = 50 and σ = 5. What share is between 45 and 60, and how many of 400?”
The share more than a distance from the mean
Use this for “Weights have μ = 500 g and σ = 2 g. How many of 500 packages are more than 3 g off?”
The 68–95–99.7 rule
Use this for “IQ scores have μ = 100 and σ = 15. About what percent are between 70 and 130?”
The value at a percentile
Use this for “Scores have μ = 500 and σ = 100. What score is at the 90th percentile?”
Margin of error of a sample proportion
Use this for “In a random sample of 400, 60% said yes. What is the margin of error?”