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Find the unknown entries a, b, c, d, e, f in the following distribution of heights of students in a class: Height Frequency Cumulative frequency (in cm) 150-155 :12 -a 155-160: b- 25 160-165 :10 -c 165-170: d -43 170-175: e- 48 175-180: 2 f Total 50

Solution Height (in cm) Frequency Cumulative frequency given Cumulative frequency 150 – 155 12 a 12 155 – 160 b... View Article

Form the frequency distribution table from the following data : Marks (out of 90) Number of candidates More than or equal to 80- 4 More than or equal to 70- 6 More than or equal to 60- 11 More than or equal to 50 -17 More than or equal to 40 -23 More than or equal to 30 -27 More than or equal to 20- 30 More than or equal to 10- 32 More than or equal to 0 -34

Solution The frequency distribution table for the given data is tabulated below: Class Interval Number of students 0-10 34 –... View Article

The following table shows the cumulative frequency distribution of marks of 800 students in an examination: Marks Number of students Below 10 -10 Below 20- 50 Below 30- 130 Below 40- 270 Below 50 -440 Below 60 -570 Below 70 -670 Below 80 -740 Below 90 -780 Below 100- 800 Construct a frequency distribution table for the data above.

Solution The frequency distribution table for the given data is tabulated below: Class Interval Number of students 0-10 10 10-20... View Article

The following is the distribution of weights (in kg) of 40 persons : Weight (in kg) 40-45 45-50 50-55 55-60 60-65 65-70 70-75 75-80 Number of persons 4 4 13 5 6 5 2 1 Construct a cumulative frequency distribution (of the less than type) table for the data above.

Weight (in kg) Cumulative frequency Less than 45 4 Less than 50 4 + 4 = 8 Less than 55... View Article

The mileage (km per litre) of 50 cars of the same model was tested by a manufacturer and details are tabulated as given below : Mileage (km/l) 10-12 12-14 14-16 16-18 Number of cars 7 12 18 13 Find the mean mileage. The manufacturer claimed that the mileage of the model was 16 km/litre. Do you agree with this claim?

Mileage (km L-1) Class –Marks (xi) Number of cars (fi) fixi 10 – 12 11 7 77 12 – 14... View Article

The weights (in kg) of 50 wrestlers are recorded in the following table : Find the mean weight of the wrestlers.

Weight (in kg) 100-110 110-120 120-130 130-140 140-150 Number of wrestlers 4 14 21 8 3 Solution: Weight (in kg)... View Article

An aircraft has 120 passenger seats. The number of seats occupied during 100 flights is given in the following table : Number of seats 100-104 104-108 108-112 112-116 116-120 Frequency 15 20 32 18 15 Determine the mean number of seats occupied over the flights.

Solution Class Interval Class Marks (xi) Frequency (fi) Deviation (di = xi – a) fidi 100 – 104 102 15 – 8... View Article

The daily income of a sample of 50 employees are tabulated as follows : Income (in Rs) 1-200 201-400 401-600 601-800 Number of employees 14 15 14 7 Find the mean daily income of employees.

Solution C.I xi di = (xi – a) Fi fidi 1 – 200 100.5 – 200 14 – 2800 201 – 400... View Article

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 –... 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... 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)... 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... 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) =... 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... 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... 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... 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... 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... 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... View Article

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