MAT 142
Lecture Video Series
Basic Terms of Probability
Objectives
• Determine the probability of a
given event .
• Determine the odds of a given
event.
• Use a Punnet square to determine
probability.
Vocabulary
• experiment
• sample space - the set S of all possible
outcomes of an experiment
• event – any subset E of the sample
space S
• probability – success divided by total
• odds – success to failures
Formulas
n (E )
p (E ) 
n (S )
o (E )  n (E ) : n (E ')
A jar on your desk contains
twelve black, eight red, ten
yellow, and five green
jellybeans. You pick a
jellybean without looking.
What is the probability that the
jellybean is green?
A jar on your desk contains
twelve black, eight red, ten
yellow, and five green
jellybeans. You pick a
jellybean without looking.
What is the probability that the
jellybean is not yellow?
A jar on your desk contains
twelve black, eight red, ten
yellow, and five green
jellybeans. You pick a
jellybean without looking.
What are the odds in favor of
picking a black jellybean?
A card is drawn from a wellshuffled deck of 52 cards.
What is the probability that
the card is a heart?
A card is drawn from a wellshuffled deck of 52 cards.
What are the odds of
drawing a heart?
A card is drawn from a wellshuffled deck of 52 cards.
What is the probability that
the card is below a 9 (ace
high)?
A card is drawn from a wellshuffled deck of 52 cards.
What are the odds of a card
below a 9 (ace high)?
A family has three
children. Using b to stand for
boy and g to stand for girl, and
using ordered triples such as
(bbg) give:
the sample space
A family has three
children. Using b to stand for
boy and g to stand for girl, and
using ordered triples such as
(bbg) give:
the event E that the family
has exactly two daughters
A family has three
children. Using b to stand for
boy and g to stand for girl, and
using ordered triples such as
(bbg) give:
the event F that the family
has at least two daughters
A family has three
children. Using b to stand for
boy and g to stand for girl, and
using ordered triples such as
(bbg) give:
the event G that the family
has three daughters
Vocabulary
•
•
•
•
dominant
recessive
Punnett square
codominant
Mendel found that snapdragons have
no color dominance; a snapdragon
with one red gene and one white gene
will have pink flowers. If a pure-red
snapdragon is crossed with a purewhite snapdragon, find the
probability of the following.
• a red offspring
• a white offspring
• a pink offspring
If carrier-detection tests show that
two prospective parents have sickle
cell trait (and are therefore
carriers), find the probability of
each of the following
• their child would have sickle cell
anemia.
• their child would have sickle cell
trait.
• their child would be healthy (free of
symptoms).
Tay-Sachs disease is a recessive
disease. If carrier-detection tests
show that one prospective parent is a
carrier of Tay-Sachs and the other
has no Tay-Sachs gene, find the
probability of each of the following.
• their child would have the disease.
• their child would be a carrier.
• their child would be healthy (free of
symptoms)
Elizabeth Jones
for
The School of Mathematical and Statistical
Sciences
at
Arizona State University
Videographer
Mike Jones