Basics of Probability and Statistics Week 1 Challenge

1.Why there is a difference in the formula of variance for population and sample

Because 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.

2. Difference between stratified and clustered sampling

Cluster Sampling- sampling is done on a population of clusters. therefore, cluster/group is considered a sampling unit.

stratified sampling- the sample is created out of the random selection of elements from all the strata while in the cluster sampling, all the units of the randomly selected clusters form a sample.

3. What is the probability of drawing 2 jacks from a pack of card.

probablilty of drawing out a Jack is 4 out of 54

4. What is the probability that both the numbers on dice are same while rolling 2 dice

The probability of both outcomes is equal i.e 1/2.

5. Why standard deviation when variance can measure the dispersion in data

The variance measures the average degree to which each point differs from the mean. While standard deviation is the square root of the variance, variance is the average of all data points within a group.