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

The cumulative frequency curve showing test scores (in marks) of 12 students is summarised in the table below.

Use this curve to find the lower quartile, upper quartile and interquartile range of the test scores.

Use the cumulative frequency graph represented by the table below to estimate the lower quartile, upper quartile and interquartile range of the waiting times (in minutes) of 24 customers.

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

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 cumulative frequency distribution of 100 customers’ ages is:

Estimate the lower quartile, upper quartile and interquartile range.

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

Use the cumulative frequency graph represented by the table below to estimate the lower quartile, upper quartile and interquartile range of a sample of 50 measurements.

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

For 120 data points the cumulative frequency table is:

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

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

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