Question

The mean of the six observations 5,15,25,35,45,55 is 30, find its variance. ​

Answer 1

Answer:

mean = 30

so,

→ sumof (difference)² = (30 - 5)² + (30 - 15)² + (30 - 25)² + (30 - 35)² + (30 - 45)² + (30 - 55)² = 25² + 15² + 5² + (-5)² + (-15)² + (-25)² = 2*625 + 2*225 + 2*25 = 1250 + 450 + 50 = 1750 .

then,

→ variance = sum of (difference)² / number of observation .

→ variance = 1750 / 6 = 291.67

Step-by-step explanation:

hope it helps you