Normal Distribution, Z-Score, and Bias Classwork

A z-score tells you...

• the standard deviation of a sampling distribution.
• the original raw score on which it is based.
• if the distribution it comes from is normal.
• how many standard deviations away from the mean a score lies.

What is the standard deviation of the distribution?

• 1010
• 20
• 60
• √20

The mean life of a tire is 30,000 km. The standard deviation is 2000 km.

Then, 68% of all tires will have a life between ___________ km and __________ km.

•  28,000 km and 32,000 km.
• 24,000 km and 34,000 km.
• 26,000 km and 34,000 km.
• 27,000 km and 31,000 km.

Tags

CCSS.HSS.ID.A.4

The distribution of heights of adult American men is approximately Normal with mean 69 inches and standard deviation 2.5 inches. Between what heights do the middle 95% of men fall? 

• 66.5-71.5
• 64-74
• 61.5-76.5
• 65-73

Tags

CCSS.HSS.ID.A.4

The normal curve is symmetrical about the mean.

• True
• False

Tags

CCSS.HSS.ID.A.4

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%
• 34%
• 16%
• 2.5%

Tags

CCSS.HSS.ID.A.4

μ = 70 , σ = 8 , X = 50 . Find z score

• 2.5
• -2.5
• 5.2
• -5.2

Tags

CCSS.HSS.ID.A.4

1) What will be the miles per gallon for a Toyota Camry when the average mpg is 23, it has a z value of 1.5 and a standard deviation of 2?

• 25

• 20

• 26

• 68

Tags

CCSS.HSS.ID.A.4

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%
• 95%
• 99.7%
• 50%

Tags

CCSS.HSS.ID.A.4

What is the purpose of using a random method to get a sample?

• A.  Reduce bias.
• B.  Reduce variability.
• C.  Increase bias.
• D. Increase variability.

Tags

CCSS.HSS.IC.B.3