Chapter 2, Problem 3CRE

(a)

To determine

To find: the percentile of a student using computer for 10 hours

Answer to Problem 3CRE

  ${70}^{\text{th }}$ Percentile is the percentile of a student using computer for 10 hours.

  

Explanation of Solution

Given:

  

Calculation:

Reading up from 10 hours on the $x$ -axis to the graphed line and then across to the $y$ -axis, we see that 10 hours corresponds to about the ${70}^{\text{th }}$ percentile. The result is shown in the below graph.

  

Conclusion:

Therefore, ${70}^{\text{th }}$ Percentile is the percentile of a student using computer for 10 hours.

(b)

To determine

To estimate: the median, $Q_1,$ and $Q_3$

Answer to Problem 3CRE

The median( ${50}^{\text{th }}$ percentile) is about 5, $Q_1$ ( ${25}^{\text{th }}$ percentile) is about $2.5$ and $Q_3$ ( ${75}^{\text{th }}$ percentile) is about 11

  

Explanation of Solution

Calculation:

The median( ${50}^{\text{th }}$ percentile) is about 5, $Q_1$ ( ${25}^{\text{th }}$ percentile)is about $2.5$ and $Q_3$ ( ${75}^{\text{th }}$ percentile) is about 11

  $IQR=Q_3-Q_1=11-2.5=8.5$

There are outliers, according to the $1.5(\text{IQR})$ rule, because values exceeding

  $Q_3+1.5(\text{IQR})=23.75\text{ clearly exist}\text{. }$

The obtained results are shown in the below graph.

  

Conclusion:

Therefore, the median( ${50}^{\text{th }}$ percentile) is about 5, $Q_1$ ( ${25}^{\text{th }}$ percentile) is about $2.5$ and $Q_3$ ( ${75}^{\text{th }}$ percentile) is about 11