The Standard Normal Curve - AFDA

The Standard Normal Curve - AFDA

Multiple Choice

Why do we use z-scores

• because they are cool

• to standardize and compare data sets

• Ms. Bergan's favorite letter is z

Multiple Select

Which are the same on a normal curve?

• Mean

• Median

• Mode

• Standard Deviation

• Range

Multiple Select

Which of the following terms describe a normal curve?

• Bell-Shaped

• Symmetric

• Unimodal

• Skew left

• Bimodal

Multiple Choice

What is the area under a normal curve?

• 1

• 99

• 95

• 68

Multiple Select

Which numbers make up the Empirical Rule?

• 68%

• 95%

• 99.7%

• 50%

• 34%

What happens when we can't use the Empirical Rule?

• The standard normal curve allows us to find probabilities for data that don't happen at even standard deviation.

Using Desmos!

• 1) Go to Desmos

• 2) Type normaldist(mean, SD)

• 3) Click the check box

• 4) Enter the range you want

Example 1

• When mean is 12 and SD is 1.3, Find P(x<10)

• 2) Type normaldist(12, 1.3)

• 3) Click the check box

• 4) Enter the range you want negative infinity to 10.

Example 2

• When mean is 12 and SD is 1.3, Find P(x>12.5)

• 2) Type normaldist(12, 1.3)

• 3) Click the check box

• 4) Enter the range you want 12.5 to infinity.

Example 3

• When mean is 12 and SD is 1.3, Find P(10.5<x<11.3)

• 2) Type normaldist(12, 1.3)

• 3) Click the check box

• 4) Enter the range you want 10.5 to 11.3.

Percentile - A Story of Big Baby Heads

From the time you were born, you were ranked in terms of your "percentile."

You might have been in the 50th percentile in height, or the 25th percentile in weight, or even in the 99th percentile for head circumference.

A Percentile ranking tells what percent of the data is BELOW that point. So if you were that baby with a head circumference in the 99th percentile, that means 99% of babies had a smaller head than you.