Basics of Probability and Statistics Week 1 Challenge

1) So, when we use N instead of N-1, we have an error called statistical bias, which means that the sample variance (the estimator) is systematically different from the true population parameter (in this case, the variance).

2) Cluster Sampling:

i) In Cluster Sampling, the sampling is done on a population of clusters therefore, cluster/group is considered a sampling unit.

ii) In Cluster Sampling, only selected clusters are sample.

iii) The aim is to reduce cost and increase the efficiency of sampling.

Stratified Sampling:

i) In Stratified Sampling, elements within each stratum are sampled

ii) In Stratified Sampling, from each stratum, a random sample is selected.

iii) The motive is to increase precision to reduce error.

3) We can calculate the sample by using SLOVIN'S FORMULA, i.e, `N/(1+Ne^2)`

4) Probability of getting 2 jacks is:

`(4/52)*(3/51) = 12/2652 = 1/22`

5) Probability that both the numbers on dice are same is:

`(6/36) = 1/6`

6) Variance helps to find the distribution of data in a population from a mean, and standard deviation also helps to know the distribution of data in population, but Standard deviation is the square root of the variance and is expressed in the same units as the data set.