If m is the arithmetic mean (average) of 4 integers a, b, c, and d and s is the standard deviation of the 4 integers and s = , then is s > 0?(1) m > a(2) a + b + c + d = 0Solution:s will be zero only in two instances: (i) when all the elements in the set are the same, or (ii) the set contains only one element, which in this case is not possible. So, we need to check whether a, … [Read more...] about Descriptive statistics – Standard Deviation
GMAT Standard Deviation
GMAT Statistics Practice – Median
Descriptive Statistics that includes mean, weighted mean, median, standard deviation and range is a GMAT favorite. At times it becomes "virulent" in its data sufficiency avatar.Here is a medium difficulty DS question from Descriptive Statistics:DirectionsThis data sufficiency problem consists of a question and two statements, labeled (1) and (2), in which certain data are … [Read more...] about GMAT Statistics Practice – Median