Notes: Percentages and Z-Scores

​Notes: Percentages and Z-scores

We will explore how to find Percentages in a normal distrubution and how to find a z-score (where a number falls on a bell curve)

A Normal Distribution will contain 100% of all data collected with in the bell curve.

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Each section of the distrubution will containg basic percentages for every type of data.

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​Normal Distrubution​

​34%

​34%

​13.5%

​13.5%

​2.35%

​2.35%

​0.15%

​0.15%

​Percentages in every normal distribution

​Special sums of common

percentages

​This is called the Emperical Rule or [68% - 95% - 99.7%] rule. Statisicians use the percentages to make all kind of Predictions.

Multiple Choice

What percent of data is $$1\sigma$$  from the mean?

• 34%

• 13.5%

• 2.5%

• 0.15%

Multiple Choice

What percent of data is less than $$\mu$$  ?

(hint: add the percentages together)

• 34%

• 16%

• 100%

• 50%

Multiple Choice

What percent of data between $$-1\sigma\ and\ 2\sigma$$  ?

(Hint: add the percentages together)

• 68%

• 81.5%

• 16%

• 95%

Multiple Choice

What percent of data greater than $$3\sigma$$ ?

• 2.5%

• 99.85%

• 0.15%

• 95%

Multiple Choice

What percent of data is $$-3\$$ standard deviations fromt he mean?

• 47.5%

• 81.5%

• 49.85%

• 50%