Lori C. answered • 03/13/18

Tutor

5.0
(21)
Algebra, Trigonometry and Calculus

The steps to find an outlier:

1. Put the data in numerical order.

2. Find the median.

3. Find the medians for the top and bottom parts of the data. This divides the data into 4 equal parts.

The median with the smallest value is called Q1. The median for all the values - usually just called the median is also called Q2. The median with the largest value is Q3.

4. Subtract...Q3 - Q1. This value is the InterQuartileRange or IQR. Remember that the range means taking the largest minus the smallest. This is a special range having to do with the quartiles.

5. Multiply...1.5 * IQR

6. Take your answer from #5 and do 2 things with it. A). Subtract it from Q1 and B) Additional to Q3.

7. Look at all your data points. If any are SMALLER than Q1 - 1.5 *IQR, they are outliers. If any are LARGER than Q3 + 1.5 *IQR, they are also outliers.

For your data....the median, Q2 is

(43+38)/2 = 40.5.

Q1 = (30+26)/2 = 28.

Q3 = (54+52)/2 = 53

The IQR is 53 - 28 = 25

1.5 * IQR = 37.5

Q1 - 37.5 = 28 - 37.5 = -9.5. There is no data value less than -9.5.

Q3 + 37.5 = 53 + 37.5 = 90.5. there is no data value greater than 90.5.

My conclusion is that there are no outliers in this data.

I hope this helps!

Emma J.

03/20/18