Mean, Median and Mode Level 1 Practice Quiz: Basic Statistics Questions
This Level 1 set tests the basics of statistics: finding the mean, median, mode and range of small data sets, along with simple variance and standard deviation. It is a free Aptitude360 practice quiz built on everyday data such as match scores, shoe sizes, temperatures and prices. Every question comes with a worked solution.
Topics covered in this Level 1 statistics set
- Mean of raw data and of a simple frequency table
- New mean after adding or removing one observation
- Correcting a mean when a value was recorded wrongly
- Median of odd and even sized data sets, including finding an unknown from a given median
- Mode of ungrouped data and the empirical relation between mean, median and mode
- Range, variance and standard deviation with the number of observations as divisor
- Effect of adding, multiplying or dividing every observation on the mean, variance and standard deviation
Key formulas for mean, median and mode
- Mean: \( \bar{x}=\dfrac{\sum x}{n} \)
- Frequency mean: \( \bar{x}=\dfrac{\sum fx}{\sum f} \)
- Empirical relation: \( \text{Mode}=3\,\text{Median}-2\,\text{Mean} \)
- Range: \( \text{Max}-\text{Min} \)
- Variance: \( \sigma^{2}=\dfrac{\sum (x-\bar{x})^{2}}{n} \)
- If \( y=ax+b \): \( \bar{y}=a\bar{x}+b,\ \sigma_{y}=|a|\sigma_{x} \)
Revision tips for basic statistics
- Always arrange the data in ascending order before finding the median.
- For a corrected mean, fix the total first: subtract the wrong value, add the right one, then divide again.
- Remember that adding a constant shifts the mean but leaves the standard deviation and variance unchanged.
- When every value is divided by a number, the variance is divided by the square of that number.
Who this Level 1 set is for
Beginners in quantitative aptitude and school students meeting central tendency and dispersion for the first time should start here before moving on to the harder levels.