Questions
The mean of five observations is 4 and their variance is 5.2. If three of these observations are 1 ,2 and 6, then the other two are
a
2 and 9
b
3 and 8
c
4 and 7
d
5 and 6
detailed solution
Correct option is C
Let the two unknown items be x and y, then Mean =4⇒1+2+6+x+y5=4⇒ x+y=11----(1)and variance = 5.2 ⇒ 12+22+62+x2+y25−( mean )2=5.241+x2+y2=55.2+(4)241+x2+y2=106x2+y2=65-----(2) Solving (1) and (2) for x and y , we get x=4,y=7 or x=7,y=4Talk to our academic expert!
Similar Questions
. If the mean of the distribution is 2.6, then the value of y is
| Variate x | 1 | 2 | 3 | 4 | 5 |
| Frequency f of x | 4 | 5 | y | 1 | 2 |
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