Example 3 - Chapter 12 Class 9 Statistics

Transcript

Example 3 A teacher wanted to analyze the performance of two sections of students in a mathematics test of 100 marks. Looking at their performances, she found that a few students got under 20 marks and a few got 70 marks or above. So she decided to group them into intervals of varying sizes as follows: 0 - 20, 20 - 30, . . ., 60 - 70, 70 - 100. Then she formed the following table: Make histogram of the data The data has class intervals of varying width. So, we calculate adjusted frequency Adjusted frequency = (𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 × 𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑠𝑖𝑧𝑒 𝑜𝑓 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙)/(𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝑠𝑖𝑧𝑒 𝑜𝑓 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙)