Basics of Probability and Statistics Week 1 Challenge

Q1: Population variance is calculated from the population data whereas Sample variance is calculated from the sample data. Hence, the is a difference of N and n-1 in the denomination of the formula. N for population and n-1 for sample data.

Q2: In clustered sampling, members of this sample are chosen from naturally divided groups called clusters, by randomly selecting elements to be a part of the sample whereas in stratified sampling, members of this sample are randomly chosen from non-overlapping, homogeneous strata.

Q3: Out of popyulation of size n we can create (n-1) number of different samples.

Q4: There are 4 Jacks in a pack of card.

probability of drawing 1st jack is 4/52.

probability of drawing 2nd jack is 3/51.

Therefore, probability of drawing 2 jacks from a pack of card is (4/52)*(3/51) i.e 1/221.

Q5: The probability that both the numbers on dice are same while rolling 2 dice is 1/2.

Q6: To maintain the consistency of units there is standard deviation when variance can measure the dispersion in data. In short standard deviation helps in getting back our original units after analysis.