NIMCET 2025
Which one of the following is NOT a correct statement?
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Answer: Option D — The variance is expressed in the same units as the units of observation
Detailed Solution
Variance is in squared units (cm² if the data are in cm); the standard deviation, not the variance, has the units of the data. So (D) is the incorrect statement.
- is true: multiplying every value by multiplies the SD by . (B) is true: SD is always at least the mean deviation about the mean.
- is true: is least when is the mean.
Quick tip
: variance carries squared units
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Statistics — Preparation
This question tests your understanding of Statistics, a key topic in the Quantitative Aptitude section. The detailed solution above uses a step-by-step approach to show the reasoning, and where available, a shortcut that helps you solve similar questions in under 90 seconds during the actual exam.
Statistics deals with collecting, summarising and interpreting data. This topic covers measures of central tendency (mean, median and mode) for ungrouped and grouped data, and measures of dispersion such as range, mean deviation, variance, standard deviation and the coefficient of variation. Exam questions test calculating these measures, the effect of adding or multiplying every observation by a constant, combined mean and variance of two groups, and comparing the consistency of two data sets. Remember that adding a constant to every value changes the mean but not the variance or standard deviation, while multiplying by k multiplies the standard deviation by |k|. Facts like these solve many questions without any calculation. Practise the statistics questions below, each with a step-by-step solution.