lecture 2

Question 1

What is the formula for the standard error?

Answer 1

Standard error = sx (standard deviation of the sample mean) / square root of sample size

Question 2

What is the effect of taking the square root of the sample size in the formula for the standard error?

Answer 2

Taking the square root of the sample size, means that the extra information from an increase in n diminishes with increasing n. (Effect is large in the beginning, then gets less when your sample is allready big)

Question 3

What does a probability distribution describe?

Answer 3

A probability distribution describes the probabilities of all mutually exclusive outcomes.

Question 4

How do you calculate the probability of two events that are mutually exclusive?

Answer 4

When two events are mutually exclusive, you apply the addition principle: Pr[A or B] = Pr[A] + Pr[B]

Question 5

How do you calculate the probabilitiy of independent events?

Answer 5

Pr[A and B] = Pr[A] x Pr[B]
This is the multiplication principle.

Question 6

What is the difference between independent events and mutually exclusive events?

Answer 6

When two events are independent, it means that the occurence of one event does not affect the probability of the occurence other event.

Two events are mutually exclusive if they cannot happen at the same time.