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प्रश्न
If the mean of observations x, x + 2, x + 4, x + 6 and x + 8 is 11,
find:
(i) The value of x;
(ii) The mean of first three observations.
उत्तर
(i) Given that the mean of observations x, x + 2, x + 4, x + 6 and x + 8 is 11.
Mean = `"Observations"/n`
11 = `[ x + x + 2 + x + 4 + x + 6 + x + 8]/5`
11 = `[ 5x + 20 ]/5`
x = `35/5`
x = 7
(ii)The mean of first three observations are
= `[ x + x + 2 + x + 4 ]/3`
= `[ 3x + 6 ]/3`
= `[ 3 xx 7 + 6 ]/3` .....[ Since x = 7 ]
= `[ 21 + 6 ]/3`
= 9.
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