The table shows the weekly income of 20 randomly selected full-time students. If the student did not work, a zero was entered.

[tex]\[
\begin{tabular}{cccc}
0 & 0 & 0 & 417 \\
\hline 171 & 355 & 343 & 212 \\
\hline 588 & 474 & 3393 & 418 \\
\hline 375 & 559 & 0 & 0 \\
\hline 113 & 546 & 394 & 105
\end{tabular}
\][/tex]

Tasks:
(a) Check the data set for outliers.
(b) Draw a histogram of the data.
(c) Provide an explanation for any outliers.

(a) List all the outliers in the given data set. Select the correct choice below and fill in any answer boxes in your choice.
A. The outlier(s) is/are _______________
(Use a comma to separate answers as needed.)
B. There are no outliers.



Answer :

Let's analyze the given data set and identify any outliers using the steps below:

1. List the data:
[tex]\(0, 0, 0, 417, 171, 355, 343, 212, 588, 474, 3393, 418, 375, 559, 0, 0, 113, 546, 394, 105\)[/tex]

2. Order the data:
[tex]\(0, 0, 0, 0, 0, 105, 113, 171, 212, 343, 355, 375, 394, 417, 418, 474, 546, 559, 588, 3393\)[/tex]

3. Determine the first quartile (Q1) and third quartile (Q3):
Q1 is the median of the first half of the data:
- First half: [tex]\(0, 0, 0, 0, 0, 105, 113, 171, 212, 343\)[/tex]
- Q1 position: [tex]\( (10 + 1) / 2 \)[/tex] = 5.5 ⇒ [tex]\(Q1\)[/tex] = [tex]\(\text{average of 5th and 6th values}\)[/tex] = (0 + 105) / 2 = 52.5

Q3 is the median of the second half of the data:
- Second half: [tex]\(343, 355, 375, 394, 417, 418, 474, 546, 559, 588, 3393\)[/tex]
- Q3 position: [tex]\((10 + 1) / 2\)[/tex] = 5.5 ⇒ [tex]\(Q3\)[/tex] = [tex]\(\text{average of 5th and 6th values}\)[/tex] = (417 + 418) / 2 = 417.5

4. Calculate the interquartile range (IQR):
[tex]\(IQR = Q3 - Q1 = 417.5 - 52.5 = 365\)[/tex]

5. Determine the lower and upper bounds for outliers:
- Lower bound: [tex]\(Q1 - 1.5 \times IQR = 52.5 - 1.5 \times 365\)[/tex] = 52.5 - 547.5 = -495
- Upper bound: [tex]\(Q3 + 1.5 \times IQR = 417.5 + 1.5 \times 365\)[/tex] = 417.5 + 547.5 = 965

Any data point less than -495 or greater than 965 is considered an outlier.

6. Identify the outliers:
In the ordered list of data:
- [tex]\(3393\)[/tex] is greater than 965.

Thus, the outlier is [tex]\(3393\)[/tex].

Summary:
(a) The outlier(s) is/are [tex]\(3393\)[/tex]

---

(b) Drawing a histogram:
To draw a histogram, divide the range of possible data values into intervals (bins) and count how many data points fall into each interval.

Binning could be as follows: [tex]\(0-199, 200-399, 400-599, 600-799, 800-\dots\)[/tex],

| Interval | Count |
|----------|-------|
| 0-199 | 8 |
| 200-399 | 5 |
| 400-599 | 6 |
| 600-799 | 0 |
| 800 and | 1 |

The histogram would have counts on the y-axis and intervals on the x-axis.

---

(c) Explanation:
The outliers likely represent unusual data points. In this case, [tex]\(3393\)[/tex] may indicate an unusually high income for a student, possibly due to a unique situation such as a high-paying job or an error in reporting data.

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