1. Max’s 2 – year checkup

2. What does that even mean, Dad?
Weight
8oth percentile
(also written as P80)
Length
90th percentile (or P90)
Head Girth
85th percentile (or P85)

3. Weights of 100 randomly selected 2 year old white American males (in pounds)24 31 29 25 27 28 26 30 20 21 33 23 22

4. Weights of 100 randomly selected 2 year old white American males (in pounds)

5. Tell me everything you can about the weights of these 2 – year olds...

6. So...what’s with Max’s “80th Percentile”?

7. How many of these 2 – year olds weigh less than 26 pounds?

8. How many of these 2 – year olds weigh less than 29 pounds?

9. How many of these 2 – year olds weigh less than 31 pounds?

10. So, Max is in the 80th percentile for his weight, because, at 31 pounds, he weighs more than 80% of 2 – year old boys.
In general, a percentile (or percentile rank) is the proportion of data that a given point exceeds.
However...

11. It might be easier to see the percentiles with the a cumulative frequency histogram...

12. ...or an ogive.

13. An ogive you
might see
one day
(or maybe
already have!)

15. “A beautiful blanket of snow hindered construction of Bend’s
St. Francis of Assisi Church in the early months of The
church’s brink foundation and arched entry are (barely) visible.”