Introduction to normal distribution  Normal Distribution and ZScores
Introduction to normal distribution
Lessons
Notes:
Properties of a Normal Distribution
$\cdot$ About 68% of the population are within 1 standard deviation of the mean.
$\cdot$ About 95% of the population are within 2 standard deviations of the mean.
$\cdot$ About 99.7% of the population are within 3 standard deviations of the mean.
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Calculator Commands
$\cdot$ To calculate the normal distribution probability between two data values:
normalcdf (lower bound, upper bound, mean, standard deviation)
 To calculate the area to the left of a data value, replace the lower bound by $1 \times 10^{99}$
 To calculate the area to the right of a data value, replace the upper bound by $1 \times 10^{99}$
$\cdot$ To calculate a data value, given the area to the left of the data value:
invNorm (area, mean, standard deviation)

2.
Using “invNorm” to Solve Normal Distribution Problems
The weight of chocolate bars produced by a factory is normally distributed with a mean of 225 grams and a standard deviation of 5 grams.