Choose the correct alternative among the following :
The class mark of the class interval 120-130 is,

Choose the correct alternative among the following : the class width of the class interval 133-139 is,

Class mark of a class is

The class mark of the class interval 4.7-6.3 is _______.

Find the class-marks of the class interval 10-25.

The class size of the class interval 60 - 68 is 8.

The class mark of the class 90-120 is

The class mark of the class 90-120 is

Class mark of class interval 60–70 is

Choose the correct alternative for each of the following questions : The class mark of the class 2000-2500 is taken as the assumed mean. What is the value of the deviation d_i for the class 2500-3000?