Calculate the interquartile range of the following data. Remember that Desmos (right-click and open in new tab/window) can be used to help you calculate some of this.

{35, 20, 41, 48, 79, 83, 83, 97, 120}

(6 points)
Put responses in the correct input to answer the question. Select a response, navigate to the desired input and insert the response. Responses can be selected and inserted using the space bar, enter key, left mouse button or touchpad. Responses can also be moved by dragging with a mouse.
Q1=
Response area

Q3=
Response area

IQR = Response area

Values lower than Response area and higher than Response area are considered outliers.

The outlier in this data set is Response area.

1 answer

To calculate the interquartile range (IQR) and identify the outlier for the provided data set {35, 20, 41, 48, 79, 83, 83, 97, 120}, we'll follow these steps:

  1. Order the data set:
    {20, 35, 41, 48, 79, 83, 83, 97, 120}

  2. Calculate Q1 (the first quartile):
    Q1 is the median of the first half of the data. The first half is {20, 35, 41, 48}.
    Median of this half = (35 + 41)/2 = 38

  3. Calculate Q3 (the third quartile):
    Q3 is the median of the second half of the data. The second half is {79, 83, 83, 97, 120}.
    Median of this half = 83 (since there's an odd number of data points in this segment)

  4. Calculate IQR (Interquartile Range):
    IQR = Q3 - Q1 = 83 - 38 = 45

  5. Determine outliers:
    We calculate the fences to find outliers:

    • Lower fence = Q1 - 1.5 * IQR = 38 - 1.5 * 45 = 38 - 67.5 = -29.5
    • Upper fence = Q3 + 1.5 * IQR = 83 + 1.5 * 45 = 83 + 67.5 = 150.5

    Any value below the lower fence or above the upper fence is considered an outlier.
    In this dataset, the only value greater than the upper fence is 120, so:

  6. Final Values:

    • Q1 = 38
    • Q3 = 83
    • IQR = 45
    • Outlier = 120

Now we can provide the answers to the input fields:

Q1 = 38
Q3 = 83
IQR = 45
The outlier in this data set is 120.