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

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

View Question

How many ways can 4 people sit in a row?

View Question

If x + y = 10 and xy = 21, what is the value of x³ + y³?

View Question

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

View Question

If a+b = 10 and ab = 21, what is the value of (a-b)^2?

View Question

What is the sum of the first 20 odd numbers?

View Question

What is the HCF of 48 and 180?

View Question

A sum triples in 20 years at simple interest. What is the rate of interest per annum?

View Question

If a number is divisible by 9, it is also divisible by which of the following?

View Question

If the radius of a circle is doubled, what happens to its area?

View Question