Question

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 those people aged between 25 and 40. Use the histogram to answer the question. The blood pressure readings were given to the nearest whole number.

Given that 400 people were aged between 25 and 40, approximately how many had a systolic blood pressure reading of 140 or higher?

Why is the answer 44?

Answer 1

The correct answer is 44.

Explanation:

From the relative frequency histogram, the relative frequency of people whose systolic blood pressure reading of 140 or higher is 0.11

Relative frequency \(=\frac{x}{400}\)

$$ \begin{aligned} 0.11 &=\frac{x}{400} \\ x &=(0.11)(400) \\ x &=44 \end{aligned} $$