Question

essential question: how do we calculate outliers from scatter plots?
learning objective:

1. students will review calculating outliers from a set of data
2. students will observe outliers from scatter plots

vocabulary: 1) scatterplot 2) quartile 3) interquartile range 4) line that best fits 5) residuals 6) outliers
iqr = q3 - q1
outliers formula
lower outlier = q1 - (1.5 x iqr)
higher outlier = q3 + (1.5 x iqr)
do now:
spiral review: define the following:
a. quartile
b. interquartile range
c. outlier
key question: how do we calculate the interquartile range and outliers from a set of data?
inter quartile range formula.
outlier formula

Explanation:

a. A quartile divides a data - set into four equal parts. Q1 is the 25th percentile, Q2 is the 50th percentile (median) and Q3 is the 75th percentile.
b. The inter - quartile range (IQR) is the range between the third quartile (Q3) and the first quartile (Q1), i.e., IQR = Q3 - Q1. It represents the middle 50% of the data.
c. An outlier is a data point that lies outside the overall pattern of the data. Lower outliers are less than Q1−1.5×IQR and higher outliers are greater than Q3 + 1.5×IQR.

Answer:

a. A quartile is a value that divides a data - set into four equal - sized parts (25% of the data each).
b. The interquartile range is the difference between the third quartile (Q3) and the first quartile (Q1), IQR=Q3 - Q1.
c. An outlier is a data point that is either less than Q1−1.5×IQR or greater than Q3 + 1.5×IQR.