Finite Math Examples

Find the Variance 6 , 12 , 15 , 22 , 18 , 14 , 8 , 17
6 , 12 , 15 , 22 , 18 , 14 , 8 , 17
Step 1
The mean of a set of numbers is the sum divided by the number of terms.
x=6+12+15+22+18+14+8+178
Step 2
Simplify the numerator.
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Step 2.1
Add 6 and 12.
x=18+15+22+18+14+8+178
Step 2.2
Add 18 and 15.
x=33+22+18+14+8+178
Step 2.3
Add 33 and 22.
x=55+18+14+8+178
Step 2.4
Add 55 and 18.
x=73+14+8+178
Step 2.5
Add 73 and 14.
x=87+8+178
Step 2.6
Add 87 and 8.
x=95+178
Step 2.7
Add 95 and 17.
x=1128
x=1128
Step 3
Divide 112 by 8.
x=14
Step 4
Set up the formula for variance. The variance of a set of values is a measure of the spread of its values.
s2=i=1n(xi-xavg)2n-1
Step 5
Set up the formula for variance for this set of numbers.
s=(6-14)2+(12-14)2+(15-14)2+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6
Simplify the result.
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Step 6.1
Simplify the numerator.
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Step 6.1.1
Subtract 14 from 6.
s=(-8)2+(12-14)2+(15-14)2+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.2
Raise -8 to the power of 2.
s=64+(12-14)2+(15-14)2+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.3
Subtract 14 from 12.
s=64+(-2)2+(15-14)2+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.4
Raise -2 to the power of 2.
s=64+4+(15-14)2+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.5
Subtract 14 from 15.
s=64+4+12+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.6
One to any power is one.
s=64+4+1+(22-14)2+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.7
Subtract 14 from 22.
s=64+4+1+82+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.8
Raise 8 to the power of 2.
s=64+4+1+64+(18-14)2+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.9
Subtract 14 from 18.
s=64+4+1+64+42+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.10
Raise 4 to the power of 2.
s=64+4+1+64+16+(14-14)2+(8-14)2+(17-14)28-1
Step 6.1.11
Subtract 14 from 14.
s=64+4+1+64+16+02+(8-14)2+(17-14)28-1
Step 6.1.12
Raising 0 to any positive power yields 0.
s=64+4+1+64+16+0+(8-14)2+(17-14)28-1
Step 6.1.13
Subtract 14 from 8.
s=64+4+1+64+16+0+(-6)2+(17-14)28-1
Step 6.1.14
Raise -6 to the power of 2.
s=64+4+1+64+16+0+36+(17-14)28-1
Step 6.1.15
Subtract 14 from 17.
s=64+4+1+64+16+0+36+328-1
Step 6.1.16
Raise 3 to the power of 2.
s=64+4+1+64+16+0+36+98-1
Step 6.1.17
Add 64 and 4.
s=68+1+64+16+0+36+98-1
Step 6.1.18
Add 68 and 1.
s=69+64+16+0+36+98-1
Step 6.1.19
Add 69 and 64.
s=133+16+0+36+98-1
Step 6.1.20
Add 133 and 16.
s=149+0+36+98-1
Step 6.1.21
Add 149 and 0.
s=149+36+98-1
Step 6.1.22
Add 149 and 36.
s=185+98-1
Step 6.1.23
Add 185 and 9.
s=1948-1
s=1948-1
Step 6.2
Subtract 1 from 8.
s=1947
s=1947
Step 7
Approximate the result.
s227.7143
 [x2  12  π  xdx ]