 Hello and welcome to the session. In this session we shall discuss the following question and the question says that 540 people are randomly chosen and were asked how many children were in their family. The results are shown in the table. If the city had 6480 families, estimate the number of families with 3 or more children, we know that experimental probability of relative frequency is given by frequency of the event divided by total number of trials. With this key idea let us proceed to the solution. In this question we are given a table showing number of children and the frequency that is the number of families having the respective number of children. It is given that there are 127 families having no child, 225 families having only one child, 125 families having 2 children, 50 families having 3 children and there are 13 families having 4 or more children. Here sample size is 540 that is total number of trials is given by 540 and we have to estimate the number of families with 3 or more children. First we find relative frequency of families having 3 or more children. Here we suppose that event A is equal to number of families having 3 or more children and this event includes frequency of 3 children and 4 or more children that is 15 and 13. So frequency of event A that is number of families having 3 or more children will be given by number of families having 3 children that is 50 plus number of families having 4 or more children that is 13 and therefore it is equal to 50 plus 13 that is 63. And from the key idea we know that relative frequency of an event is given by frequency of the event divided by total number of trials. So experimental probability of event A that is equal to the relative frequency will be given by frequency of the event that is given by 63 upon total number of trials which is equal to 540. Now the question is if the city had 6480 families the number of families with 3 or more children will be given by 63 upon 540 multiplied by 6480 and therefore we get 9 into 6 is 54 and 9 multiplied by 72 will be equal to 648 and again we get 616 and 6 into 12 is 72. So we are left with 63 into 12 which is equal to 756 thus approximately 756 families will have 3 or more children which is the required answer. This completes our session. Hope you enjoyed this session.