Statistics and Probability Unit
Lesson #1 – What is Probability?
Probability- the odds that an event will happen; can
be represented as a number from 0 to 1
0%
50%
100%
impossible
0.5
certain
Approximate the following probabilities.
1) You will miss a day of school before the end of the year
2) A tossed coin will land “heads up”
3) The next President of the US will be over 21 yrs old
4) The next baby born in Vermillion will be a girl
5) You will graduate from high school
Probabilities can also be written as fractions:
Probability of a simple event,
P(e) = number of favorable outcomes
total number of possible outcomes
A standard dice is rolled (faces are numbered 1-6)
P(1) = ______
P(2) = ______
P(3) = ______
P(4) = ______
P(5) = ______
P(6) = ______
P(even) = ______
P(more than 4) = ______
P(less than 5) = ______
A bag contains 5 red balls and 4 green balls. One ball
is drawn from the bag.
P(red) = ______
P(green) = ______
P(yellow) = ______
A deck of cards contains 52 cards (13 of each
suit). One card is drawn.
A, K, Q, J, 10, 9, 8, 7, 6, 5, 4, 3, 2
P(ace) = ______
P(not an ace) = ______
P(ace of hearts) = ______
P(hearts) = ______
P(red) = ______
P(not red) = ______
Use the table to determine the following probabilities.
Write the probabilities as fractions and percents.
100 people were asked to choose their favorite
subject, math or science.
Math
Science
Boys
31
19
Girls
26
24
P(boy likes math)= ______ P(girl likes math) = ______
P(like math) = ______
P(don’t like math) = _____
50 people were surveyed about their favorite
footwear.
Sandals Tennis Shoes Boots
Boys
3
12
9
Girls
13
7
6
P(sandals) = ______
P(tennis shoes) = ______
P(boots) = ______
P(sandals or boots) = ______
P(boy chooses sandals) = ______
P(girl chooses sandals) = ______