This preview shows pages 1–5. Sign up to view the full content.
1
Statistics 511
Random Variables and Probability Distributions
Relevant Sections:
4.6 – 4.8
(4.6) Variables
Random variable
a.
Qualitative
b.
Quantitative
1.
Discrete
2.
Continuous
(4.7) Discrete Random Variables
Probability distribution of Y – gives the possible values of Y (denoted by y) and
corresponding probabilities P(y).
Ex. Y = the number of heads when 2 coins are tossed. What is P(y)?
Properties
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document 2
(4.8) Binomial Random Variable/ Probability Distribution
Characteristics:
P(y) =
Mean:
Standard deviation:
Ex. Suppose that a woman plans to have 5 children.
Suppose also that the probability of
a boy is .51 at each birth and the sexes of successive children are independent.
Find the
following probabilities:
a.
None of the children are boys
b.
There are exactly 3 boys
c.
There are at least
2 boys
d.
All of the 5 children are boys
3
Statistics 511
Relevant Sections:
4.9 – 4.10
(4.9) Continuous Random Variables and Probability Distributions
f(y)
Graphical representations:
Total area under the curve
P(a < y <b)
Important notes:
(4.10) Normal Distribution
Normal probability (density) function:
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document 4
Common notation:
Standard normal random variable
See Table 1 on pp1091 – 1092
Standardization:
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 04/28/2008 for the course ST 511 taught by Professor Prof.kimweems during the Spring '08 term at N.C. State.
 Spring '08
 Prof.KimWeems

Click to edit the document details