Basics of Probability and Statistics Week 1 Challenge

Q1.Why there is a difference in the formula of variance for population and sample

Ans- Population varience refers to the value of variance that is calaculated

from population data and sample variance is the variance calculated from

sample data. due to this value of denominator is the formula variance in

case of samle data is n-1 and its is n for population data

Q2. Difference between stratified and clustered sampling

Ans- 1)in stratified sampling is one in which population devided into homogenous segments and then sample is randomly taken from segments.

1)in cluster sampling refers to wherein the members of the population are selected at random, from natuarally occuring groups called 'Cluster'.

Q3.How many different samples can be created out of population of size n.

Ans- If population size is n. then we can created different samples more than size n.

Q4.What is the probability of drawing 2 jacks from a pack of card.

Ans- Probability= no of fovrable events/ no of possible events.

= 2/52 = 1/26.

Q5.What is the probability that both the numbers on dice are same while rolling 2 dice.

Ans- Probability= no of fovrable events/ no of possible events.

=6/36 = 1/6.

Q6.Why standard deviation when variance can measure the dispersion in data.

Ans- we have maintained the consistancy with respect to units. so we take square root of variance that is known as standard deviation. in this way dispersion go back to its original units.