Quiz 2

If I tell you that you scored at the 55th percentile on your final exam, you would know:

• 55% of the class scored as good or worse than I did 
• I earned a 55% on the exam
• I failed the exam
• 45% of the class scored worse than I did 

Tags

CCSS.6.SP.A.2

CCSS.6.SP.B.5

What percentile is 74 in the following group of data? 35, 65, 68, 100, 23, 69, 74, 70, 61, 90, 85, 55, 30, 65, 80

• 73rd

• 90th

• 75th

• 27th

Given the data set: 1, 2, 3, 6, 9, 11, 45, 102, calculate the percentile rank for 11.

• 70^th percentile

• 62.5^th percentile

• 72.5^th percentile

• 75^th percentile

What does a z-score of -3.1 mean?

• The data point is 3.1 units below the mean.
• The data point is 3.1 units above the mean.
• The data point is 3.1 standard deviations below the mean.
• The data point is 3.1 standard deviations above the mean.

Tags

CCSS.HSS.ID.A.4

The weights of miniature horses are roughly normally distributed with a mean of 230 pounds and standard deviation of 45 pounds.
What proportion of miniature horses weigh between 185 and 275 pounds? 

• 50%
• 68%
• 95%
• 99.7%

Tags

CCSS.HSS.ID.A.4

Adam's Z-score on a test is +2.5.  What does this mean?

• He'd better start studying.
• He did better than EVERYONE.
• He scored 2.5 standard deviations above the average.
• He did terrible.

Tags

CCSS.HSS.ID.A.4

Joanne's Z-score is -1.5.  What does this mean?

• She didn't take the test yet.
• She scored 1.5 standard deviations below the average.
• She did better than most people.
• No clue

If Gonzalo's score is 87, the class average is 82, and the SD is 4, what is Gonzalo's Z-score?

• -1.25
• +1.25
• +1.20
• +1.02

Tags

CCSS.HSS.ID.A.4

Jill's Z-score on the same test was a +3.0.  (average was 82 and SD was 4).  
What was her actual score?

• 85 %
• 79 %
• 94 %
• 40 %

Suppose that a normal model describes the acidity (pH) of rainwater, and that water tested after last week’s storm had a z-score of 1.8. This means that the acidity of the rain 

• had a pH 1.8 higher than average rainfall. 
• had a pH of 1.8. 
• varied with standard deviation 1.8 
• had a pH 1.8 standard deviations higher than that of average rainwater. 

Tags

CCSS.HSS.ID.A.4