1. Review for test Ch. 6 ON TUESDAY:
Study notes, HW, Daily Grades, Quiz
p – #85 – 95 (more practice for
Section 6.3)
p – 460 #98, 100 – 106

2. Advanced Placement Statistics
Section 7.1: Discrete and Random Variables
EQ: How do you calculate the probability of a random variable?

3. Terms to Know:
Random Variable --- variable with a numerical outcome;
notation is capital X
Always DEFINE your Random Variable:
X = number of heads from tossing a coin
X = number of hours spent studying
ETC…

4. Discrete Random Variables --- countable number of outcomes; corresponds to specific points on the number line
Recall:
Properties of a Probability Distribution
1) 0 < p(x) < 1

5. probability histograms:
Ex. The following table represents a probability distribution for a DRV, X. What is P(X = 6)?
P(X = 6) = .35
create
probability histograms:
Distributions

6. RECALL:
Frequency vs Relative Frequency
actual counts
of outcome
count of outcome relative to whole

7. X = number of girls in a randomly selected family of
In class: p #2
a) Create the sample space.
{GGG, GGB,GBG,GBB,BBB,BBG,BGB,BGG}
S = ______________________________
X = number of girls in a randomly selected family of
3 children
b) Create a probability distribution for this sample space.
0.125
0.375
0.375
0.125

8. a) Write your answer 2 ways.
p #3
a) Write your answer 2 ways.
P(X > 1)
P(X > 0)
P(X > 1) = = 0.9 b)
P(X < 2) means “no more than 2 non-word errors” or “fewer than 3 non-word errors”.

9. Continuous Random Variable --- assumes values associated with intervals on the number line; infinite number of outcomes
Probability Distribution of a CRV --- defined
by a density curve

10. Area under Probability of Density Curve = CRV
Recall:
Area under Probability of
Density Curve = CRV
Ex. For the CRV X, find P(X = 0.8).
0.02
P(0.79 < X < 0.81) = ______
P(0.799 < X < 0.801) = _____
0.002
0.0002
P( < X < ) = _____
***As X  0.8, P(X = 0.8)  ______

11. No distinction between > and >
Therefore:
NO PROBABILITY exists at single values of X on a CRV density curve. WHY??
NO Area exists if there aren’t 2 dimensions.
No distinction between > and >
No distinction between < and <
Assignment: p #7, 8

12. N (, )
Recall:
Normal Distribution

13. Standard Normal Distribution

14. Assignment:
p #7, 8
p #12, 13, 15, 17
Review for test Ch. 6 ON TUESDAY:
Study notes, HW, Daily Grades, Quiz
p – #85 – 95 (more practice for Section 6.3)
p – 460 #98, 100 – 106