Archives

The following table gives the number of pages written by Sarika for completing her own book for 30 days : Number of pages written per day 16-18 19-21 22-24 25-27 28-30 Number of days 1 3 4 9 13 Find the mean number of pages written per day.

Solution Class Marks Mid – Value (xi) Number of days (fi) fixi 15.5 – 18.5 17 1 17 18.5 – 21.5 20 3... View Article

Calculate the mean of the following data : Class 4 – 7 8 -11 12- 15 16 -19 Frequency 5 4 9 10

Solution The given data is not continuous. So, we subtract 0.5 from the lower limit and add 0.5 in the upper limit of each class. Class... View Article

Calculate the mean of the scores of 20 students in a mathematics test : Marks 10-20 20-30 30-40 40-50 50-60 Number of students 2 4 7 6 1

Solution Let us first determine the class mark xi of each class and then proceed as follows Class Class Marks (xi) Frequency... View Article

Find the mean of the distribution : Class 1-3 3-5 5-7 7-10 Frequency 9 22 27 17

We first, find the class mark xi of each class and then proceed as follows. Class Class Marks (xi) Frequency (fi) fixi 1-3 2... View Article

Apoorv throws two dice once and computes the product of the numbers appearing on the dice. Peehu throws one die and squares the number that appears on it. Who has the better chance of getting the number 36? Why?

Given Apoorv throw two dice at once. Peehu throws one die and squares the number that appears on it Find out We have to determine who has the... View Article

A game consists of spinning an arrow which comes to rest pointing at one of the regions (1, 2 or 3) (Figure). Are the outcomes 1, 2 and 3 equally likely to occur? Give reasons.

Solution Total number of outcome = 360 The probabalites p(1)= 90/360 =1/4 p(2) = 90/ 360 = 1/4 p(3) = 180/360 =1/2 Hence, we... View Article

In a family having three children, there may be no girl, one girl, two girls or three girls. So, the probability of each is 1/4. Is this correct? Justify your answer.

Solution No it is incorrect that in a family having three children, there may be no girl, one girl, two girls or three girls, the probability of... View Article

Will the median class and modal class of grouped data always be different? Justify your answer.

The value depends on the type of data given. The median class and modal class of grouped data is not always different, it depends on the... View Article

Is it true to say that the mean, mode and median of grouped data will always be different? Justify your answer.

No, the values of mean, mode and median of grouped data can be the same as well, it depends on the type of data given. The average taken for a... View Article

The median of an ungrouped data and the median calculated when the same data is grouped are always the same. Do you think that this is a correct statement? Give reason.

To calculate the median of a grouped data, the formula applied here is based on the assumption that the observations in the classes are evenly... View Article

Which of the following cannot be the probability of an event? (A)1/3 (B) 0.1 (C) 3% (D)17/16

The correct answer is (D)17/16 Solution Probability of an event always lies between 0 and 1. Probability of any event cannot be more than 1... View Article

If an event cannot occur, then its probability is (A)1 (B) 3/4 (C) 1/2 (D) 0

The correct answer is (D) 0 Solution The event which cannot occur is said to be impossible event. The probability of impossible event = zero... View Article

Consider the following distribution : Marks obtained Number of students :More than or equal to 0 63, More than or equal to 10 58, More than or equal to 20 55, More than or equal to 30 51, More than or equal to 40 48, More than or equal to 50 42, The frequency of the class 30-40 is (A) 3 (B) 4 (C) 48 (D) 51

The correct answer is (A) 3 Solution Marks Obtained Number of students Cumulative Frequency 0-10 (63 – 58) = 5 5... View Article

The times, in seconds, taken by 150 athletes to run a 110 m hurdle race are tabulated below The number of athletes who completed the race in less than 14.6 seconds is : A11 (B) 71 (C) 82 (D) 130

Class 13.8-14 14-14.2 14.2-14.4 14.4-14.6 14.6-14.8 14.8-15 Frequency 2 4 5 71 48 20 The correct answer is (C)... View Article

Consider the data : The difference of the upper limit of the median class and the lower limit of the modal class is A0 (B) 19 (C) 20 (D) 38

Class 65-85 85-105 105-125 125-145 145-165 165-185 185-205 Frequency 4 5 13 20 14 7 4 The correct answer... View Article

For the following distribution: Marks Number of students Below 10 3, Below 20 12, Below 30 27, Below 40 57, Below 50 75, Below 60 80. The modal class is (A)10-20 (B) 20-30 (C) 30-40 (D) 50-60

The correct answer is (C) 30-40 Solution According to the given details, Marks Number of students Cumulative Frequency Below 10... View Article

Consider the following frequency distribution: Class: 0-0,5 6-11, 12-17, 18-23, 24-29 Frequency: 13, 10 ,15 ,8 ,11 The upper limit of the median class is (A)17 (B) 17.5 (C) 18 (D) 18.5

The correct answer is (B) 17.5 Solution According to the given details, Classes are not continuous, hence, we have to make the data continuous... View Article

For the following distribution : Class: 0-05, 5-10 ,10-15 ,15-20, 20-25 Frequency :10, 15, 12 ,20, 9 the sum of lower limits of the median class and modal class is (A)15 (B) 25 (C) 30 (D) 35

The correct answer is (B) 25 Solution Class Frequency Cumulative Frequency 0-5 10 10 5-10 15 25 10-15 12 37... View Article

The abscissa of the point of intersection of the less than type and of the more than type cumulative frequency curves of a grouped data gives its (A) mean (B) median (C) mode (D) all the three above

The correct answer is (B) Median Solution The middle value in the data set is called Median. The median of a set of data is the middlemost... View Article

In the formula x = a + h(fiui/fi), for finding the mean of grouped frequency distribution, ui = (A) (xi + a)/h (B) h (xi – a) (C) (xi -a)/h (D) (a – xi)/h

The correct answer is (C) (xi –a)/h Solution The given formula is the step deviation formula which is used to calculate the... View Article