Question

the mean of 6 observations 15,25,35,45,55 is 30 find it's variance​

Answer 1

Answer:

350

Step-by-step explanation:

$\frac{a + 15 + 25 + 35 + 45 + 55}{6} = 30$

=> a + 175 = 180

=> a = 5

$=\frac{(5 - 30)^{2} + (15 - 30)^{2} + (25 - 30)^{2} + (35 - 30)^{2} + (45 - 30)^{2} + (55 - 30)^{2} }{5}$

$= \frac{ {25}^{2} + {15}^{2} + {5}^{2} + {5}^{2} + {15}^{2} + {25}^{2} }{5}$

$= \frac{625 + 225 + 25 + 25 + 225 + 625}{5}$

$= \frac{1750}{5}$

= 350