JEE Main 2019 — Statistics Question with Solution
From: JEE Main 2019 (Online) 10th January Morning Slot
Question
The mean of five observations is 5 and their variance is 9.20. If three of the given five observations are 1, 3 and 8, then a ratio of other two observations is -
Choose an option
Show full solutionCorrect option: C
Correct answer
C4 : 9
Step-by-step explanation
Let two observations are x1 & x2
mean =
. . . . (1)
variance =
. . . . . (2)
(x1 + x2)2 2x1x2 = 97
169 - 2x1x2 = 97
or x1x2 = 36
x1 : x2 = 4 : 9
mean =
. . . . (1)
variance =
. . . . . (2)
(x1 + x2)2 2x1x2 = 97
169 - 2x1x2 = 97
or x1x2 = 36
x1 : x2 = 4 : 9
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