1. WARM – UP Mean = Range = Median = Standard Dev. = IQR = 3 4 1.41 2
1.) Identify the Mean, Standard Deviation, Median, Range and IQR for each data set: Which values are Robust?
a.) 1, 3, 3, 3, 5 b.) 1, 3, 3, 3, 5, 300
Mean =
Range =
Median =
Standard Dev. =
IQR = 3 4
1.41 2
Mean =
Range =
Median =
Standard Dev. =
IQR =
52.5
299 3
121.25 2
2.) Domestic house cats have an average weight of 10 lbs.
σ = 3 lbs. What are you more likely to find, a cat weighting 6 lbs. or one weighing 15 lbs.?

2. 2.) Domestic house cats have an average weight of 10 lbs.
σ = 3 lbs. What are you more likely to find, a cat weighting 6 lbs. or one weighing 15 lbs.?
Normalcdf(-E99, )
= 0.091
Normalcdf(1.667,E99)
= 0.048

3. CENTER, UNUSUAL, SPREAD, SHAPE
WARM - UP
What are the four characteristics that one comments on when asked to analyze a HISTOGRAM or BOXPLOT?
CENTER, UNUSUAL, SPREAD, SHAPE
Univariate data

4. Associations among Bivariate Data
CHAPTER 7
Associations among Bivariate Data
A Scatterplot shows the relationship between two quantitative variables.

5. Interpreting Scatterplots
The Scatterplot reveals Form, Direction, and Strength.
FORM:
Linear Patterns
Non-Linear = Curved Patterns
Clusters
DIRECTION:
Positively Associated – Upward linear trend.
Negatively Associated – Downward linear trend.

6. 0.5 ≤ |r|< 0.9 = MODERATELY STRONG |r| ≥ 0.9 = VERY STRONG
STRENGTH:
The CORRELATION measures strength (how linear the data is) and direction of the linear relationship between two quantitative variables. Symbol = r
-1 ≤ r ≤ 1
|r| < = WEAK
0.5 ≤ |r|< = MODERATELY STRONG
|r| ≥ = VERY STRONG

7. Different Correlation Strengths

8. Different Correlation Strengths

9. Describe the association’s Form, Direction, and Strength
CORRELATION = r
Is there a relationship between student quiz grades and their test grade?
Quiz Avg. 75 86 92 95 80
Test Avg. 79
100 90
Describe the association’s Form, Direction, and Strength

10. Quiz Avg. 75 86 92 95 80
Test Avg. 79
100 90
r = ¼ [ ]
r = ¼ (3.382) =

11. Quiz Avg. 75 86 92 95 80
Test Avg. 79
100 90 99
Quiz Avg. 75 86 92 95 80
Test Avg. 79
100 90
r =
r =

12. Page 160: 5,6,11,12,17,20

13. Page 160: 5,6,11,12,17,20

14. FACTS ABOUT CORRELATION
Positive r refers to positively associated variables while negative r refers to negatively associated variables. (The Pos./Neg. sign of ‘r’ matches the slope’s sign.)
2. Correlation is ALWAYS between -1 ≤ r ≤ 1. The correlation is strong when r is close to 1 or -1 but weak when r is close to zero.
3. r has NO UNITS.
4. Correlation is only valuable for LINEAR relationships.
Like the Mean and Std. Dev., Correlation is non-resistant and is very influenced by outliers.

15. NEGATIVELY ASSOCIATED, and STRONG
EXAMPLE:
A new antibacterial cleaner is introduced to a Petri dish.
SECONDS:
BACTERIA POP.:
Construct a Scatterplot and describe the form, direction, and strength.
LINEAR,
NEGATIVELY ASSOCIATED, and STRONG
with r =
BACTERIA
SECONDS