Question

a survey about the cost of cell phone plans was given to 100 people. the five - number summary of the survey results is shown. the number of people who pay more than $60 is. the number of people who pay less than $72 is.

Explanation:

Step1: Recall the property of median

The median divides the data set into two equal - halves. If there are \(n = 100\) data points (people in this case), the median is the 50th and 51st ordered data points (when \(n\) is even). The number of data points above the median is \(\frac{n}{2}\).
Since \(n=100\), the number of people who pay more than the median (\(M = 60\)) is \(\frac{100}{2}\).

$$ \frac{100}{2}=50 $$

Step2: Recall the property of the third - quartile

The third - quartile (\(Q_3\)) represents the value below which \(75\%\) of the data lies. If \(n = 100\), the number of data points below \(Q_3\) is \(0.75n\).
Substitute \(n = 100\) into \(0.75n\):

$$ 0.75\times100 = 75 $$

Answer:

The number of people who pay more than \(\$60\) is \(50\). The number of people who pay less than \(\$72\) is \(75\).