Theory

This is one of those subjects where students can dramatically improve their scores by putting in some practice. But donâ€™t just solve the entire set by force, put in some smart work. Learn the tricks of calculation given below and put them to use every time you solve a set. The crux of doing well in Data Interpretation is accurately solving in less time. Most of the students are able to understand what is asked and how to do it. The only difference between a high scorer and a low scorer is accuracy and speed. As most of the questions are interrelated (as in the data derived from one is used by another) these errors can get compounded during the exam. Make sure you spend enough time accurately solving those questions where the data derived will be used by the other questions. Use the techniques given below to improve your time.

Tip

Averages: In case you have to calculate the average of a group of numbers (for eg marks) which are distributed around some round number. For example to find the average of 94, 97, 92, 89, 84 and 99. These numbers are distributed around 90. Find the difference of these numbers as compared to 90 and take and average of that number. Hence we calculate the average of 4, 7, 2, -1, -6 and 9 ~ 15/6=2.5. Hence the average of marks = 90+2.5=92.5

Tip

In case numbers are not given adjoining bar graphs, column charts, pie charts etc, write them down on paper before proceeding. It reduces the chances of error by incorrectly reading a graph in the midst of solving a problem.

Formula

1) Average = Sum/ (number of readings)

2) Percentage of A wrt B = A*100/B

Solved Example

[IBPS 2013 Clerk]

Study the table carefully and answer the questions:

1) What is the respective ratio between the number of pages printed by Printer B in 2nd week and the number of pages printed by Printer F in 5th week?

a) 4:9 b) 11:13 c) 9:13 d) 7:11 e) 9:11

Solution: The ratio is obtained by dividing the respective values. ie. 441/693 = 7/11

2) What is the average number of pages printed by all the printer in the 4th week?

a) 375 b) 425 c) 415 d) 430 e) 390

Solution: The average is determined by the sum of the values / number of values = (256 + 563+ 347+ 651+ 412+ 321)/ 6 = 425