![]() In our case, because we are using ages, this means that no matter how young our friend may be, we would not consider them an outlier. Even though it’s not possible to have a negative age, our outlier calculation only considers the numerical values. Notice that the thresholds for the outliers are simply defined by the data we use. This means that we would consider any ages that are below -3.5 or above 88.5 to be outliers. Let’s break that down using our original example. The most common method of finding outliers with the IQR is to define outliers as values that fall outside of 1.5 x IQR below Q1 or 1.5 x IQR above Q3. Now that we know how to find the interquartile range, we can use it to define our outliers. The interquartile range, or IQR, is 22.5 Finding Outliers with the IQR Minor Outliers (IQR x 1.5) That is, 75% of values are equal to or lower than 54. That is, 50% of values are equal to or lower than 41.5. This is also the 50th percentile or median. That is, 25% of values are equal to or lower than 31.5. We can also refer to these values in the following way. This means that the interquartile range would be 54 - 31.5, or 22.5. In this case, the “middle” value, between each of the groups, is the average of the values on either side of the line: Instead of finding the middle number, we can break the ages in half, and then in half again. And, if we split the groups in half, there also isn’t a number that falls in the middle of either half. With it ordered, it would look like this.Īs we can see, because the total number is even, there isn’t a number that falls in the middle of the groups. Let’s say we had these 12 ages, instead of our original 15. ![]() But we can still work out the interquartile range if we had an even number of ages and couldn’t find middle values. This method of breaking the groups in half, finding the middle number and repeating this for each half works perfectly with a collection of 15 ages. The IQR is the difference between these two values. We then find the middle value in the bottom group, which is 31 in our example. We calculate the interquartile range by first finding the value in the middle of the top group, which is 54 in this case.So the middle value for each group will be in the 4th position. All ages between 21 and 38 are in the bottom group, and all of our ages between 45 and 64 are in the top group. We can use the median to split our two groups. As we can see, the age 43 is in the 8th position. ![]() If we have 15 ages, the middle age will be at the 8th position.You can also see their position below each number. Once we’ve ordered them from smallest to largest, they’ll look like this.First we start off will all of our ages unordered. Find the difference between the middle of the top and bottom groups. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |