Basics of Probability and Statistics Week 1 Challenge

1. Population variance refers to the value of variance that is calculated from population data, and sample variance is the variance calculated from sample data. Due to this value of denominator in the formula for variance in case of sample data is ‘n-1’, and it is ‘n’ for population data. As a result both variance and standard deviation derived from sample data are more than those found out from population data.

2. Relatedly, in cluster sampling you randomly select entire groups and include all units of each group in your sample. However, in stratified sampling, you select some units of all groups and include them in your sample.

3. n factorial size.

4. Probability is : .0045

5. probability of getting both same numbers on the dice: 1/6 = .166

6. Standard deviation is came into existance even though varaince can measure the dispertion becuase whnever we calculate variance, it will square the values and measuring unit. Becuase of that even after calculating the variance we can not compare variance with the actual values. Therefore, standard deviation came into existance, which will calculate the deviation by taking square of the variance So, it will convert the parameter to the original units. Then we can compare the deviation with the actual value in the data.