mean median mode

Quartiles

​Quartiles break data into four groups (quarters)

The 2nd Quartile (Q2) is the same as the median... it's the middle number.

Quartiles

​Quartiles break data into four groups (quarters)

The 2nd Quartile (Q2) is the same as the median... it's the middle number.

The 1st Quartile (Q1) is the middle number of all values LOWER than the median

Quartiles

​Quartiles break data into four groups (quarters)

The 2nd Quartile (Q2) is the same as the median... it's the middle number.

The 1st Quartile (Q1) is the middle number of all values LOWER than the median

The 3rd Quartile (Q3) is the middle number of all values GREATER than the median

Quartiles

​Quartiles break data into four groups (quarters)

The 2nd Quartile (Q2) is the same as the median... it's the middle number.

The 1st Quartile (Q1) is the middle number of all values LOWER than the median

The 3rd Quartile (Q3) is the middle number of all values GREATER than the median

The INTERQUARTILE RANGE (IQR) is

equal to Q3 - Q1

​Sometimes there is no "middle number". In that case, you find the average of the two values on each side of the middle. This rule works for the 1st and 3rd quartiles too.

​The Quartiles, along with the min (smallest value) and max (largest value) make up what's called the 5 number summary of the data.

The 5 number summary of example 2 ...

min: 1 Q1: 2 Q2: 4 Q3: 12 Max: 18

The 5 number summary is displayed using box-and-whisker plots...

Notice how 25% (or 1/4) of the data falls in each part of the box and whisker plot

A box-and-whisker plot of example 1 would look like this....

(remember the 5 number summary...

min: 3 Q1: 8 Q2: 12 Q3: 19 Max: 40)

A box-and-whisker plot of example 2 would look like this....

(remember the 5 number summary...

min: 1 Q1: 2 Q2: 4 Q3: 12 Max: 18)

Multiple Choice

What is the first quartile from the given plot?

• 12

• 20

• 15

• 28

Multiple Choice

What's the longest incubation time?

• 35

• 20

• 15

• 28

Multiple Choice

What percent of the birds have incubation times between 15 and 28 days?

• 25

• 50

• 75

• 100

Multiple Choice

What fraction of the birds have incubation times of 15 days or less?

• 1/4

• 1/2

• 1/15

• 3/4

​Assignment: IXL Algebra 1

ii.3 and hh.9
(90% smart score)