NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 13: Statistics and Probability

Exercise 13.1

In the formula \(\bar{x}=a+\dfrac{\sum f_i d_i}{\sum f_i}\), for finding the mean of grouped data, \(d_i\)'s are deviations from \(a\) of

While computing mean of grouped data, we assume that the frequencies are

If \(x_i\) are the class marks and \(f_i\) the corresponding frequencies with mean \(\bar{x}\), then \(\sum f_i(x_i-\bar{x})\) equals

In the formula \(\bar{x}=a+h\,\dfrac{\sum f_i u_i}{\sum f_i}\) for mean of grouped data, \(u_i=\)

The abscissa of the intersection point of the less-than and more-than cumulative frequency curves of a grouped data gives its

For the following distribution:

the sum of lower limits of the median class and modal class is

Consider the distribution:

The upper limit of the median class is

For the following distribution:

The modal class is

Consider the data:

The difference of the upper limit of the median class and the lower limit of the modal class is

Times (s) taken by 150 athletes in a 110 m hurdle race:

The number who finished in less than 14.6 s is

Consider:

The frequency of the class 30–40 is

If an event cannot occur, its probability is

Which of the following cannot be the probability of an event?

An event is very unlikely to happen. Its probability is closest to

If the probability of an event is \(p\), the probability of its complementary event is

The probability expressed as a percentage of a particular occurrence can never be

If \(P(A)\) denotes the probability of an event A, then

A card is selected from a deck of 52 cards. The probability that it is a red face card is

The probability that a non-leap year selected at random will contain 53 Sundays is

When a die is thrown, the probability of getting an odd number less than 3 is

A card is drawn from a deck of 52 cards. Event \(E\): “card is not an ace of hearts”. The number of outcomes favourable to \(E\) is

The probability of getting a bad egg in a lot of 400 is 0.035. The number of bad eggs in the lot is

A girl finds the probability of winning the first prize in a lottery to be 0.08. If 6000 tickets are sold, how many tickets has she bought?

One ticket is drawn at random from a bag of tickets numbered 1 to 40. The probability that the selected ticket is a multiple of 5 is

Someone is asked to take a number from 1 to 100. The probability that it is a prime is

A class has 23 students: 4 from house A, 8 from B, 5 from C, 2 from D and the rest from E. One student is selected at random to be the monitor. The probability that the selected student is not from A, B and C is