Topic Details (Notes format)

How to Calculate Variance and Standard Deviation

Subject: Mathematics

Book: Maths Mastery

Variance measures how spread out data values are around the mean, calculated by averaging the squared differences from the mean. Standard deviation is the square root of variance, returning the measure to the original data units. For a dataset [2, 4, 4, 6, 8], the mean is 4.8, each difference is (2 – 4.8)², (4 – 4.8)², etc., then averaged to get variance, and the square root yields the standard deviation. Higher standard deviation indicates greater spread. These metrics are fundamental in statistics, quality control, finance risk, and any field requiring data analysis. Familiarity with variance and standard deviation fosters statistical literacy and well-informed decisions.

Practice Questions

If the probability of an event is 1/4, what is the probability of its complement?

View Question

If a cylinder has a radius of 7 cm and height of 10 cm, what is its volume?

View Question

The LCM of two numbers is 60, and their HCF is 5. If one of the numbers is 20, what is the other number?

View Question

If sin(A) = 1/2 and A is acute, what is the value of A?

View Question

The simple interest on Rs. 4000 at 5% per annum for 2 years is:

View Question

A square is inscribed in a circle with a radius of 5 cm. What is the area of the square?

View Question

If a:b = 7:9 and b:c = 5:6, what is a:c?

View Question

The area of an equilateral triangle with side length 6 cm is:

View Question

If a right triangle has legs of 9 cm and 12 cm, what is the length of the hypotenuse?

View Question

What is the area of a sector of a circle with radius 14 cm and central angle 90°?

View Question