Question Type 3: Finding the quartiles using the cumulative frequency graph Exercises

Use the cumulative frequency table below for 28 observations to find the first quartile, third quartile and interquartile range.

A large survey yields the following cumulative frequency distribution for 150 responses:

Estimate the first quartile, the third quartile, and the interquartile range.

A cumulative frequency curve for a sample of 80 observations has the following table of values:

Use this curve to estimate the first and third quartiles and the interquartile range.

The cumulative frequency distribution for 45 test scores is given by:

Estimate $Q_1$, $Q_3$ and the interquartile range.

A cumulative frequency table for 36 measurements is shown below. Use it to estimate $Q_1$, $Q_3$ and the interquartile range.

The following cumulative frequency table shows the waiting times, $t$ minutes, of 24 customers.

Estimate the values of the lower quartile ($Q_1$), the upper quartile ($Q_3$), and the interquartile range (IQR).

The cumulative frequency table below summarises 60 observations. Estimate the lower quartile, upper quartile and interquartile range.

The cumulative frequency distribution for daily sales (in units) of a store over 20 days is given below:

Estimate $Q_1$, $Q_3$ and compute the interquartile range, showing any interpolation.

The following table summarizes the cumulative frequency of test scores (in marks) for 12 students.

Find the lower quartile, the upper quartile and the interquartile range of the test scores.

The table below shows the cumulative frequency distribution for a sample of 50 measurements.

Estimate the lower quartile ($Q_1$), the upper quartile ($Q_3$), and the interquartile range ($IQR$).

The cumulative frequency distribution of 100 customers’ ages is given in the table below:

Estimate the lower quartile ($Q_1$), the upper quartile ($Q_3$), and the interquartile range (IQR).

For 120 data points, the cumulative frequency table is as follows:

Use this table to estimate $Q_1$, $Q_3$ and the interquartile range (IQR).