The lifetime of all the batteries produced by a certain company in a year have a distribution that is symmetric about the mean "m". If the distribution has the standard deviatin "d", what percent of the distribution greater than m+d?
1)68% of the distribution lies in the interval from m-d to m+d, inclusive
2)16% of the distribution less than than m-d.
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Standard deviation
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NehaPathak
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m,d
B) 16% less than m-d. as symmetrical wrt to m, thus 16% greater then m+d sufficient
A) 68% in interval. thus 32% outside interval. thus 16% greater than m+d (symmetry)
IMO D
B) 16% less than m-d. as symmetrical wrt to m, thus 16% greater then m+d sufficient
A) 68% in interval. thus 32% outside interval. thus 16% greater than m+d (symmetry)
IMO D
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If the distribution is symmetric about the mean then it means that 50% of the population is above and below the mean.NehaPathak wrote:The lifetime of all the batteries produced by a certain company in a year have a distribution that is symmetric about the mean "m". If the distribution has the standard deviatin "d", what percent of the distribution greater than m+d?
1)68% of the distribution lies in the interval from m-d to m+d, inclusive
2)16% of the distribution less than than m-d.
(1) 68% of the distribution lies in the interval from m-d to m+d implies that 34% is either above or below the mean. Out of 100, 32% population is outside 1 SD of the mean so 16% of the population is m + d and 16% as m - d; SUFFICIENT.
(2) 16% of the distribution less than than m - d is again the same as the info given in statement 1; SUFFICIENT.
The correct answer is D.
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