Re: Is the standard deviation of salaries of teachers in school A greater
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26 May 2021, 09:11
The standard deviation of a set of values means how spread apart the values are from the mean.
Coming to the statements:
Statement 1: mean salary of the teachers in school A > median of the salaries of the teachers in school B
This statement doesn't give us anything on the actual salaries. We can straight away discard this statement.
However, for understanding let us take an example.
Example 1: Suppose salaries of teacher in school A: {10, 20, 30, 40, 50} whereas in school B: {10, 11, 12, 13, 14}
where mean(A) > mean(B) and SD(A) > SD(B)
Example 2: Suppose salaries of teacher in school A: {10, 20, 30, 40, 50} whereas in school B: {10, 11, 12, 13, 50}
where mean(A) > mean(B) and SD(A) < SD(B)
Hence statement 1 alone is not sufficient.
Statement 2: mean salary of the teachers in school A > mean salaries of the teachers in school B
This statement as well doesn't give us anything on the actual salaries. We can straight away discard this statement.
We can use the same example to prove that this statement is also not sufficient.
Hence the correct answer is Option E.