Name: 
 

Dispersion 2


 1 
Tanner and Robbie discovered that the means of their grades for the first semester in Mrs. Merrell’s mathematics class are identical.  They also noticed that the standard deviation of Tanner's scores is 20.7, while the standard deviation of Robbie's scores is 2.7.  Which statement must be true?
a)
In general, Robbie's grades are lower than Tanner's grades.
b)
Robbie's grades are more consistent than Tanner's grades.
c)
Robbie had more failing grades during the semester than Tanner had.
d)
The median for Robbie's grades is lower than the median for Tanner's grades.
 

 2 
Jean’s scores on five mathematics tests were 98, 97, 99, 98, and 96.  Her scores on five English tests were 78, 84, 95, 72, and 79.  Which statement is true about the standard deviations for the scores?
a)
The standard deviation for the English scores is greater than the standard deviation for the math scores.
b)
The standard deviation for the math scores is greater than the standard deviation for the English scores.
c)
The standard deviations for both sets of scores are equal.
d)
More information is needed to determine the relationship between the standard deviations.
 

 3 
What is the best approximation of the standard deviation of the measures mc003-1.jpg?
a)
1
c)
5
b)
2
d)
10
 

 4 
The term "snowstorms of note" applies to all snowfalls over 6 inches.  The snowfall amounts for snowstorms of note in Utica, New York, over a four-year period are as follows:
7.1, 9.2, 8.0, 6.1, 14.4, 8.5, 6.1, 6.8, 7.7,
21.5, 6.7, 9.0, 8.4, 7.0, 11.5, 14.1, 9.5, 8.6
What are the mean and population standard deviation for these data, to the nearest hundredth?
a)
mean = 9.46; standard deviation = 3.74
c)
mean = 9.45; standard deviation = 3.74
b)
mean = 9.46; standard deviation = 3.85
d)
mean = 9.45; standard deviation = 3.85
 



 
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