1. WARM - UP What percent of students are Females in a freshman class?
Freshman Sophomore Junior Senior
Male
Female
287
203
What percent of students are Females in a freshman class?
What percent of the Freshman class students are females?
What percent of males represent the senior class?
What percent of the senior class are males?
14.5%
35.9%
19.9%
57.6%

2. WARM – UP
Eye Color
Blue
Brown
Hazel
3 or below
14.0%
61.0%
25.0% 4+
13.5%
60.8%
25.7%
Blue
Brown
Hazel
3 or below
129
561
230 4+ 73
330
139
GPA
920
542
Determine if an association exists between ones eye color and ones GPA at a large school. Justify your answer by examining the conditional distribution of eye color among the two levels of GPA.
Since the Distribution of eye color is relatively the same for each GPA level, eye color had little to do with your GPA. (No Association = Independent variables)

3. Displaying Quantitative Distributions
Chapter 4
Displaying Quantitative Distributions
I. Histograms: A bar graph representing quantitative values and frequency.

4. II. Dotplots: A dotplot places a dot along an axis for each case in the data instead of a bar.
The dotplot to the right shows Kentucky Derby winning times, plotting each race as its own dot.
You might see a dotplot displayed horizontally or vertically.

5. Describing Distributions
When describing a distribution, comment on: Center, Unusual features, Shape, and Spread.
When describing a distribution, comment on: Center, Unusual features, Shape, and Spread.
You are expected to….
CUSS

6. CENTER:
The center is a numerical value that attempts to summarize the approximate ‘typical value’ of the distribution. “Average”
UNUSUAL:
You should always mention any stragglers, or outliers, that stand off away from the body of the distribution. If any gaps are present in the distribution, we might have data from more than one group.

7. SHAPE:
1. A histogram with one main peak is dubbed unimodal; histograms with two peaks are bimodal.
2. A distribution with NO mode is called Uniform and is roughly flat.

8. SHAPE (continued):
3. A distribution is symmetric if the right and left sides (tails) are mirror images of each other.
Skewed to the Right
Appr.
Symmetric
Skewed to the Left

9. SPREAD: RANGE = Highest - Lowest
The spread is a numerical summary of how tightly the values are clustered around the center.

10. Displaying Quantitative Distributions with a Histogram
Ex.) Thirty seeds were planted in each of 8 containers with an experimental fertilizer. After 2 weeks the number of germinated seeds was then recorded.
12, 15, 12, 22, 10, 14, 16, 20
Center - ≈ 14
Unusual - Nothing
Shape - ≈ Skewed Right
Spread - ≈ 12 data
15 graph
Frequency
Number of germinating seeds

11. Describe the following Distribution.
Shape – Skew Right
Center - ≈ 18
Spread - ≈ 38 15 10 5
Shape – ≈ Symmetric
Unusual-
Center - ≈ 82
Spread - ≈ 38
No. of Customer Service Phone Calls

12. COMPARE the following Distribution.15 10 5
No. of Customer Service Phone Calls B
Shape: A – Skew Right B – Appr. Normal
Center: B has a LARGER center than A
Spread: A and B have about the SAME Spread

13. HW: Page 65: 5-10 Center ≈ 10 Unusual - NOTHING Shape ≈ Bimodal
Main Peak = Skewed Right
Spread ≈ 35

14. HW: Page 65: 5-10 Shape ≈ Unimodal = Skewed Right Center ≈ 3
Spread ≈ 8

15. HW: Page 65: 5-10 Shape ≈ Bimodal Shape ≈ Skewed Right
Center ≈ 12
Spread ≈ 24
Shape ≈ Symmetric
Center ≈ 46
Spread ≈ 26

16. HW: Page 65: 5-10