Standard Deviation quizziz

For a certain type of computer the length of time between battery charges is normally distributed with a mean of 50 hours and a standard deviation of 15 hours. Select the values (2 answers) that represent the range of the charging time within 2 standard deviations of the mean.

• 50

• 35

• 80

• 65

• 20

• 1" (inch)

• 3" (inches)

• 4" (inches)

• 6" (inches)

• 12" (inches)

The number of absences during fall semester was recorded for each student in a large elementary school. The distribution of absences is displayed in the following cumulative relative frequency graph. What is the IQR for the distribution of absences?

• 1

• 2

• 3

• 5

• 1

• The mean of the distribution is E.

• The area between B and F is .50.

• The median of the distribution is C.

• The 3rd quartile of the distribution is D

• The area under the curve between A and G is 1.

Tags

CCSS.6.SP.B.4

CCSS.HSS.ID.A.1

A class assignment has a mean of 85% and a standard deviation of 6. Find your z-score if you earned a 76% on this assignment.

• z = -1.1

• z = -2.1

• z = - 5

• z = -1.5

Tags

CCSS.HSS.ID.A.4

What percent of people within 3 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

Tags

CCSS.HSS.ID.A.4

• 4.83 inches

• 5.18 inches

• 6.04 inches

• 8.93 inches

• The standard deviation cannot be computed from the given information.

In the diagram, the shaded area represents approximately 95% of the scores on a standardized test. If these scores range from 78 to 92, which could be the standard deviation?

• 3.5

• 7.0

• 14.0

• 20.0

In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. Approximately 95% of molds filled by this machine will hold weights in what interval? 

• 1084 to 1216 pounds 
• 1106 to 1150 pounds 
• 1106 to 1194 pounds 
• 1128 to 1172 pounds

Tags

CCSS.HSS.ID.A.4

What percent of people within 2 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

Tags

CCSS.HSS.ID.A.4