Tuesday, 21 June 2016
What is Probability?
= Probability is the chance that something will happen - how likely it is that some event will happen,
Example 1:
Suppose a coin is flipped 3 times. What
is the probability of getting two tails and one head?
Solution: For this experiment, the sample space
consists of 8 sample points.
S = {TTT, TTH, THT, THH, HTT, HTH, HHT,
HHH}
Each sample point is equally likely to
occur, so the probability of getting any particular sample point is 1/8. The
event "getting two tails and one head" consists of the following
subset of the sample space.
A = {TTH, THT, HTT}
The probability of Event A is the sum of
the probabilities of the sample points in A. Therefore,
P(A) = 1/8 + 1/8 + 1/8 = 3/8
**In this case,you can use a tree
diagram to look at which is getting two tails and one head faced coin.
Example 2:
Two dice are thrown
together.
Use a tree diagram to find the probability that one number is even and the other is odd.
Use a tree diagram to find the probability that one number is even and the other is odd.
Of these, three are even: {2, 4, 6} and three are odd: {1, 3, 5}
So, the tree diagram looks like this:
So the probability that one number is even and the other is odd
Video:
*Note: if there something you wanna ask just leave a comment, thank you! :D*
hi its me again i got some question on prabability too, here it is.
ReplyDeleteTickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?
oh hi, to answer your question all you need to do is.
ReplyDeleteS = {1, 2, 3, 4, ...., 19, 20}.
Let E = event of getting a multiple of 3 or 5 = {3, 6 , 9, 12, 15, 18, 5, 10, 20}.
P(E) = n(E/n(S)= 9/20