a nurse measured the blood pressure of each person who visit

a nurse measured the blood pressure of each person who visited her clinic. following is a relative frequency histogram for the systolic blood pressure readings for people aged between 25 and 40. the blood pressure readings were given to the nearest whole number. what class width was used to construct the relative frequency distribution?

Solution

Blood pressure range

Level

Less than 120

Normal

120-139

Pre-hypertension

140-159

High blood pressure (Hypertension stage 1)

160 -179

High blood pressure

(Hypertension stage 2)

More than 180

Hypertensive crisis

The above table defines the category of systolic blood pressure.

From the above table it is clear that width of histogram for showing the relative frequency of number of patients lie in particular blood pressure category should be 20.