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Home Q & A Board Science-Related Homework Help Mathematics
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Stevbo Stevbo
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7 years ago Edited: 7 years ago, Stevbo
The following data were obtained from a survey of college students. The variable X represents the number of nonassigned books read during the past six months.

x          0       1       2       3       4       5       6
P (X=x)       0.55       0.15       0.10       0.10       0.04       0.03       0.03

What is the variance of X? Place your answer, rounded to two decimal places in the blank. For example, 4.56 would be a legitimate entry.
Post Merge: 7 years ago

Bio_Man, any advice on this one?
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#1
Staff Member
6 years ago
Multiply each x value by its corresponding P(X = x) value

0*0.55 = 0
1*0.15 = 0.15
2*0.10 = 0.20
3*0.10 = 0.30
4*0.04 = 0.16
5*0.03 = 0.15
6*0.03 = 0.18

Now add up the products:
0+0.15+0.20+0.30+0.16+0.15+0.18 = 1.14 
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