Hi All,

Presenting the visual representation of the normal distribution curve:

A normal distribution curve is also known as the bell curve.

Such questions on standard deviation are centered around the following 4 variables:

I. Mean of the distribution

II. Standard Deviation of the distribution

III. A data point of the distribution

IV. Distance of data point from the mean

These variables are related as

Data Point = Mean +/- Distance from the mean where the distance from mean is expressed in terms of standard deviation

Out of these 4 variables, the question is likely to give you 3 and ask you to find the fourth variable.

Let's see what have we been given in the question statement

I. Mean- Need to find (let's assume it to be \(m\))

II. Standard deviation of the distribution - \(2\)

III. A data point of the distribution- \(43\)

IV. Distance of data point from the mean - \(3\) standard deviations below mean

We can write

\(43 < m - 3 * 2\)

( we put in a '-' sign as the data point is below mean)\(m > 49\). Out of the given options only Option E has a value greater than \(49\).

Hope this helps

Regards

Harsh

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Ace GMAT quant

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