1. Graphs: Quartiles
Divide data into 4 equal parts

2. Graphs: Quartiles Divide data into 4 equal parts
Q2 divides data into 2 equal parts.
What do we usually call Q2?

3. Graphs: Quartiles Median Divide data into 4 equal parts
Q2 divides data into 2 equal parts.
What do we usually call Q2?
Median

4. Graphs: Quartiles
How do you determine Q1 and Q3?

5. Graphs: Quartiles How do you determine Q1 and Q3?
Consider the data set:
12, 5, 3, 29, 1

6. Graphs: Quartiles How do you determine Q1 and Q3?
Consider the data set:
12, 5, 3, 29, 1
Reorder data: 1, 3, 5, 12, 29

7. Graphs: Quartiles How do you determine Q1 and Q3?
Consider the data set:
12, 5, 3, 29, 1
Reorder data: 1, 3, 5, 12, 29

8. Graphs: Quartiles How do you determine Q1 and Q3?
Consider the data set:
12, 5, 3, 29, 1
Reorder data: 1, 3, 5, 12, 29

9. Graphs: Quartiles Consider the data set: 12, 5, 3, 29, 1
Reorder data: 1, 3, 5, 12, 29
Q1 = 2 Median (Q2) = 5 Q3= 20.5

10. Graphs: Page 39, E1 Bimodal Skewed right Skewed left
Approximately normal
Roughly uniform

11. Graphs: Page 39, E1
The distribution for a recent year is shown here, and the shape of the distribution is typical.

12. Graphs: Page 39, E1
This distribution is strongly skewed left. Students
will often have the height of the bar for 85+ taller
than that for 75–84, confusing actual number of
deaths with probability of death. There are fewer
people in the 85+ category than in the 75–84
category, so there are fewer deaths.

13. Graphs: Page 39, E1 b. This distribution will be strongly skewed
right. Most people get their driver’s licenses
at the earliest possible age or quite close to
it.

14. Graphs: Page 39, E1 c. The distribution of SAT scores for a large
number of students should be approximately
normal.

15. Graphs: Page 39, E1 few very expensive models (like Corvettes)
d. Selling prices of new cars should show a
few very expensive models (like Corvettes)
and a large number of relatively inexpensive
(but not cheap!) ones (around $15,000 to
$20,000).
The distributions should be skewed right
(toward the larger values.)

16. Graphs: Page 39, E3 a and b

17. Graphs: Page 39, E3
Uniform distribution that shows sort of data from rolling a fair die 6000 times

18. Graphs: Page 39, E3
Roughly normal distribution with mean 15 and standard deviation 5

19. Graphs: Page 54, E17

20. Graphs: Page 54, E17 I. Graph D, because on an easy test most people
get high scores.

21. Graphs: Page 54, E17 I. Graph D, because on an easy test most people
get high scores.
II. Graph A, because the distribution of heights has two
modes (mothers and daughters).

22. Graphs: Page 54, E17 I. Graph D, because on an easy test most people
get high scores.
II. Graph A, because the distribution of heights has two
modes (mothers and daughters).
III. Graph C, because most countries in the Olympics get
no medals at all and only a very small number of countries
get multiple medals.

23. Graphs: Page 54, E17 I. Graph D, because on an easy test most people
get high scores.
II. Graph A, because the distribution of heights has two
modes (mothers and daughters).
III. Graph C, because most countries in the Olympics get
no medals at all and only a very small number of countries
get multiple medals.
IV. Graph B, because the weights should be
mound-shaped. Most chickens will be clustered near a
central weight with decreasing numbers having lower or
much higher weights.

24. Questions?