B is the one without calculus I belive...
anyways
so descriptive statistics
I\'m doing the 2004 AP Statisics AP test Section II part A
like my teacher gives us old exams and this is one of those questions
the question asks for a boxplot
there are outliers
the IQR gives me a value were there is an observation on the point were I take Q1 - IQR to find outliers... is an observation that fall on exactly Q1 - IQR an outlier???
To answer your question, no, an observation that falls exactly on Q1 - IQR is not necessarily an outlier. Let me explain how to find outliers in a boxplot using the IQR (Interquartile Range).
1. First, you need to calculate the IQR, which is the range between the first quartile (Q1) and the third quartile (Q3). The formula for the IQR is:
IQR = Q3 - Q1
2. Next, you identify any potential outliers. Outliers are defined as observations that are either below Q1 - 1.5 * IQR or above Q3 + 1.5 * IQR. These boundary values are commonly used, but they can vary depending on the context or specific guidelines provided.
3. If there are any observations that fall below Q1 - 1.5 * IQR or above Q3 + 1.5 * IQR, they are considered potential outliers and are represented as individual data points outside the boxplot. These points are marked separately, often as circles or asterisks, to indicate their outlier status.
4. However, it's important to note that an observation falling exactly on Q1 - IQR is not necessarily an outlier. It is simply the lower boundary for identifying potential outliers. Similarly, an observation exactly on Q3 + IQR is not necessarily an outlier, but rather the upper boundary for potential outliers.
Remember, outliers represent extreme values that differ significantly from the rest of the data. They may indicate errors in data collection, measurement issues, or unusual data points. It's crucial to consider the context and the specific guidelines provided to determine whether to treat an observation as an actual outlier or an influential data point.