Question

If the mean of the following data is 7.5,then find the value of 'a'..marks 5 6 7 8 9 0..no.of students 3 10 17 À 8 4

Answer 1

Step-by-step explanation:

 Total                                        42+A                    306+8A

Sum of frequency (f1) =42+A

Sum of f1x1      = 306+8A

Given mean is 7.5

Mean xˉ=Σf1Σf1x1

∴7.5=41+A306+8A

⇒306+8A=7.5(42+A)

⇒306+8A=315+7.5A

⇒8A−7.5A=315−306

⇒0.5A=9

⇒A=18