PROBABILITY(LECTURE 4)

Probability (lecture 4)

Good morning Boys...........

Guidelines for the class:

1. Note down  the work in your register on a regular basis.

2. Please feel free to ask, if you have any doubt by dropping a message in the comment box.

3. Make a column on the right hand side, if you need to do any rough work

4. Write  today's date.

5. Write the chapter number and name.

6. Text in red has to be noted down as its your class work.

7. Text in green has to be read thoroughly and understood.
8. Text in blue are hyperlinks, click on those to view videos

Today's Learning Outcomes are :

I will be able to :

(i) Recall the formula of probability

(ii) Calculate the probability related to tossing of dice.

Now we have to get a fair idea about dice!!!!!

Let us now watch this video, to understand the probability of throwing a die equally likely events.

CLICK on the link to watch it now👇

https://youtu.be/eHJ40sSkYLE

The term equally likely is now clear to us ....

Let us see what are the possible outcomes when two dice are thrown together with the help of this link 👉   https://youtu.be/HWZcU6cc_2Y

Before we try to solve related questions, see some more examples through videos 

Probability of getting sum greater than three 

CLICK on the link to watch it now👇

 https://youtu.be/QfI969WYJG4

Note: Not greater than means less than or equal to.

Are you ready to solve some questions???

Q 1. A die is rolled, find the probability that an even number is obtained.
Solution: 

Let us first write the sample space S of the experiment.

S = {1,2,3,4,5,6}Let E be the event "an even number is obtained" and write it down.E = {2,4,6}We now use the formula of the classical probability.P(E) = n(E) / n(S) = 3 / 6 = 1 / 2

Q 2.Two dice are rolled, find the probability that the sum is
a) equal to 1
b) equal to 4
c) less than 13
Solution:

a) The sample space S of two dice is shown below.
S = { (1,1),(1,2),(1,3),(1,4),(1,5),(1,6)
(2,1),(2,2),(2,3),(2,4),(2,5),(2,6)
(3,1),(3,2),(3,3),(3,4),(3,5),(3,6)
(4,1),(4,2),(4,3),(4,4),(4,5),(4,6)
(5,1),(5,2),(5,3),(5,4),(5,5),(5,6)
(6,1),(6,2),(6,3),(6,4),(6,5),(6,6) }Let E be the event "sum equal to 1". There are no outcomes which correspond to a sum equal to 1, hence
P(E) = n(E) / n(S) = 0 / 36 = 0
b) Three possible outcomes give a sum equal to 4: E = {(1,3),(2,2),(3,1)}, hence.
P(E) = n(E) / n(S) = 3 / 36 = 1 / 12
c) All possible outcomes, E = S, give a sum less than 13, hence.
P(E) = n(E) / n(S) = 36 / 36 = 1

DO ALL THE FOLLOWING EXERCISE QUESTIONS IN YOUR REGISTER

Boys, few sums of exercise 15.1 are not solved here, do those questions as your home work.

Global Goals, are a universal call to action to end poverty, protect the planet and ensure that all people enjoy peace and prosperity. Let us refer SDG 1

Thank you and see you all  tomorrow