# NCERT Solutions for Class 12 Maths Chapter 13 Exercise 13.2

NCERT Solutions for Class 12 Maths Chapter 13 Exercise 13.2 in Hindi and English Medium updated for academic session 2020-2021. All the contents like PDF solutions and Video solutions are free to use without any login or password.

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## Class 12 Maths Chapter 13 Exercise 13.2 Solutions

Class: 12 | Mathematics |

Chapter: 13 | Probability |

Exercise: 13.2 | Hindi and English Medium Solution |

### Class 12 Maths Chapter 13 Exercise 13.2 in Hindi and English Medium

### Class 12 Maths Chapter 13 Exercise 13.2 in Videos

#### Conditional Probability

For mobile, download Class 12 Maths App in English Medium and कक्षा 12 गणित App in Hindi Medium. So far, in probability, we have discussed ways of finding the probability of events. If we have two events from the same sample location, does information about the occurrence of one event affect the probability of another event? Let us try to answer this question by doing a random experiment in which the result is equally likely. Consider the use of tossing three appropriate coins.

The sample space for the experiment contains 8 digits. Now suppose that the first coin is given a tail, what is the probability of having two heads? With information on the occurrence of the first coin, we believe that cases in which the first coin does not result should be considered when the possibility of two heads is explored. This information reduces our sample space. In other words, the additional information actually tells us that the condition can be considered as a new random experiment for which the sample space contains only those results that are compatible with the occurrence of the event.

###### Mean of a Random Variable

The mean or expectation of a random variable x is the sum of the products of all possible values of x by their respective probabilities.

##### Why do we find variance?

The mean of a random variable does not give us information about the variability in the values of the random variable. In fact, if the variance is small, the values of the random variable are close to the mean. Random variables with different probability distributions may have similar means.