I am going through the variance and standard deviation. Can you please let me know what is the reason and purpose of learning of these topics. Can you give me real world examples to apply this knowledge. The course misses on the question of “What is the need and purpose of learning a concept”.
The variance and standard deviations both measure how spread out a distribution is. They are very useful in finding probabilities or areas under a distribution specially of a normal distribution..
The graphs below show an illustration of distribution with different means and variances. The flatter distribution has variance 9 while the steeper one has lesser variance, 4.
Knowing the variance or standard deviation of a distribution helps us describe its variability which is needed in further analysis. This will be explained in later videos of the course.
Hope this helps.
The 365 Team