Question

The following are the marks obtained by 50 college students in a certain test.

Take suitable width of the class interval marks using struge’s rule.

Answer 1

Here, N= 50; Range = H.V.-L. V. = 49-12 = 37

The number classes as per Sturge’s rule are obtained as follows: 

Number of class intervals (K) = 1 + 3.322 logN = 1 + 3.22 log 50 = 1 + (3.22 × 1.6990) = 6.47 = 7

classes (Approx.) Size/width of class intervals – e = Range/Number of class intervals) = 37/7

5.28 = 6 (Approx.)

The size/width of each class is 6 and there are 7 classes. Thus, the required continuous frequency distribution with exclusive class intervals width is prepared as :

Frequency distribution of marks of students