The normal distribution

What is the the total area under the standard normal distribution curve?

• 100
• 25
• .5
• 1

If 10 is added to every value in a set of data, what will happen to the value of the mean?

• it will increase by 10
• it will decrease by 10
• it will stay the same
• it will both increase and decrease

If 10 is added to every value in a set of data, what will happen to the value of the standard deviation?

• it will increase
• it will decrease
• it will stay the same
• it will both increase and decrease

Which is NOT true about the standard normal distribution?

• It is bell-shaped.
• It is unimodal.
• The mean is 0 and the standard deviation is 1.
• It is asymmetrical.

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%

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

CCSS.HSS.ID.A.3

CCSS.HSS.MD.A.2

Find P (-1.26 < z < 3.25). 

• 0.0047
• 0.9204
• 0.8956
• 0.4981

Tags

CCSS.HSS.ID.A.4

The mean number of accidents a week at a company is 6.4 with a standard deviation of 1.5.  What proportion of weeks would you expect to have less than 5 accidents?

• 0.6915
• 0.1753
• 0.8238
• -0.93

The scoring of modern IQ is such that Intelligence Quotients (IQs) have a normal distribution of μ= 100 and 𝞂 = 15.

Mensa International is a non-profit organization that accepts only people with IQ score within the top 2%. What integer level of IQ qualifies one to be a member of Mensa?

• 130
• 131
• 145
• 120

A manufacturer contracts to supply ball bearings with diameters between 24.60mm and 25.4mm. Product analysis indicates that the ball bearings manufactured have diameters that are normally distributed with a mean of 25.10mm and a standard deviation of .20mm. What percentage of ball bearings fail to satisfy the contract specifications?

• 92.7%
• 7.3%
• 48.2%
• 33.2%