Re: In a certain sample of data, mean is 23 and standard deviation is 3.5.
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17 Sep 2023, 02:10
OE
.It is given that mean = 23 and standard deviation = 2.5
We have to find the values which are less than 2 standard deviations from the mean.
We know that, deviation of the terms from the mean can be on both the sides, either
less than the mean or more than the mean
Where, M = Mean
D = Standard Deviation
m, if we see the points marked on the right of mean, all the
points are at a deviation of less than 2D. So that’s why, any point lying between M
and M + 2D will be having its deviation less than 2 standard deviations from the
mean value.
Similarly
If we take from M-2D to M, we see the points marked on the left of the mean, all the
points are at a deviation of less than 2D. So that’s why, any point lying between M
and M - 2D will be having its deviation less than 2 standard deviations from the mean
value.
Now, as per the question, M = 23
And, D = 3.5
So, 2 standard deviation = 2D = 7
So, the values 16 and 30 are exactly 2 standard deviations away from the mean.
But we are looking for those values which are less than 2 standard deviations from
the mean.
So, it can take any value between 16 and 30.
Hence, the possible values as per the options will be 17, 18 and 28.
Ans. (D, E, F)