Login

Ref : AnswerPosted by manmeet.singh (MeritNation Expert),

If we take number of class intervals according to the the given data, then in which circumstances the formula "RANGE/CLASS SIZE" is used?

If we go by formula, then we will have to use 10 class intervals whereas going by suggestion of Mr. Manmit Singh, we will have to use 11.

My following question has not been answered yet. Please answer.

In which circumstances are we required to calculate NUMBER OF CLASSES by dividing "RANGE" by "CLASS SIZE"?

Is it correct to calculate NUMBER OF CLASSES (which is 10 as per my calculation) in the following example?

Construct a frequency table with class intervals 0-5 (5 not included) of the following marks obtained by a group of 30 students in an examination.

0, 5, 7, 10, 12, 15, 20, 22, 25, 27, 8, 11, 17, 3, 6, 9, 17, 19, 21, 29, 31, 35, 37, 40, 42, 45, 49, 4, 50, 16

Asked bysamit v22 hours, 34 minutes agoSubject:Math 1Answer

CLASS INTERVAL

TALLY MARKS

FREQUENCY

0 – 5

///

3

5 – 10

////

5

10 – 15

///

3

15 – 20

////

5

20 – 25

///

3

25 – 30

///

3

30 – 35

/

1

35 – 40

//

2

40 – 45

//

2

45 - 50

///

3

Posted byRia Varghese(student) 1 hour, 33 minutes ago
0 1

If second observation 5 was included in class "5-10" then why 29th observation that is 50 was included in class '45-50"?

Do we need to create one more class for 50? In that case number of classes will be 11. Whereas range divided by class size =number of classes that is 10.

Posted bysamit v(student) 0 seconds ago
Asked bysamit v23 hours, 36 minutes agoSubject:Math 1Answer

Yes, you are correct. The 29th observation i.e., 50 should not be included in the interval 45-50. The observation 50 should be included in the interval 50-55.

So, make another class interval 50-55 which has one tally mark entry and frequency as 1.

The class interval 45-50 would have two tally mark entries and frequency as 2.

Posted bylalit.mehra...(MeritNation Expert) 4 hours, 13 minutes ago
My main question remained unanswered as to whether it will be correct to have 11th class?

A class interval is of form (a – b) where a is included and b is not included.

The formula for calculating number of class intervals, which is

is valid in almost all cases.

This question is a special case in which the formula is violated because of the observation 50 as it cannot be included in the class interval (45 – 50).

So, we have to make another interval (50 – 55) to include the observation 50.

Hence the number of class intervals = 10 + 1 = 11.

  • 1
View Full Answer
What are you looking for?