Enter the total number of observations into the calculator to determine the lowest quartile. This calculator can also evaluate any of the variables given the others are known.

Lowest Quartile Formula

The following formula is used to calculate the lowest quartile (Q1) in a data set.

Q1 = 1/4 * (N + 1)


  • Q1 is the lowest quartile N is the total number of observations in the data set

To calculate the lowest quartile, add 1 to the total number of observations in the data set. Then, multiply the result by 1/4. The result is the position of the lowest quartile in the ordered data set. If this is not an integer, round up and down to get two positions and take the average of the corresponding values.

What is the Lowest Quartile?

A Lowest Quartile, also known as the first quartile or Q1, is a statistical term that represents the 25th percentile of a given data set. This means that 25% of the observations fall below this value. It is a type of quantile, which divides the range of a probability distribution into continuous intervals with equal probabilities. The lowest quartile is used in descriptive statistics for data analysis and can be determined using various methods, including the step method and the weighted average method.