The box plot below shows the total amount of time, in minutes, the students of a class surf the Internet every day: A box plot is shown. The left-most point on the plot is 20 and the right-most point is 95. The box is labeled 40 on the left edge and 60 on the right edge. A vertical line is drawn inside the rectangle at point 50.

Part A: List two pieces of information that are provided by the graph and one piece of information that is not provided by the graph. (4 points)

Part B: Calculate the interquartile range of the data, and explain in a sentence or two what it represents. (4 points)

Part C: Explain what affect, if any, there will be if an outlier is present. (2 points)

A) the median, the first quartile, the third quartile, the minimum and the maximum are provided; the mean is not provided.  B) IQR = 25.  C) An outlier would make the "whisker" portion longer and could potentially slightly shift the box

Step-by-step explanation:

A) A box plot is created from what is known as the "five number summary."  This includes:  

Minimum;

Maximum;

First Quartile;

Median;

and Third Quartile.

The mean is not listed on the five-number summary.

B) To find the interquartile range (IQR) we subtract the third and first quartiles:

60-35 = 25

C) An outlier would be much larger than the rest of the data or much smaller than the rest of the data.  Since it would add another data point, this could slightly shift the entire box (quartiles and median) as well as extend the "whiskers" (the segments from the box to the minimum or maximum values.

part a: list two pieces of information that are provided by the graph and one piece of information that is not provided by the graph. (4 points)

two pieces of information that are provided by the graph:

the lower quartile (q1) = 37.5

the upper quartile (q3) = 60

one piece of information that is not provided by the graph:

the median is the middle value of the data set = 50

part b: calculate the interquartile range of the data, and explain in a sentence or two what it represents. (4 points)

interquartile range of the data = q3 - q1 = 60 -37.5 = 22.5

interquartile range is the distance between the first quartile and the third quartile. it is the amount of spread in the middle 50 percent of a data-set

part c: explain what affect, if any, there will be if an outlier is present. (2 points)

in this case, 95 is far away from q3 (60) so 95 is an outlier. it will effect the mean and median of the data.

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