First slide

Introduction to statistics

Question

If the arithmetic mean of the following data is 7, then
$a + b =$
$x_{i}$ 4 6 7 9
$f_{i}$ a 4 b 5

Easy

Solution

We have,
$\begin{array}{l} 7 = \frac{4 a + 24 + 7 b + 45}{a + 4 + b + 5} \\ \Rightarrow 4 a + 7 b + 69 = 7 a + 7 b + 63 \Rightarrow a = 2 \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App