L2: prob

Question 1

addition rule

Answer 1

P(X or Y) = P(X) + P(Y) - P(X & Y)

Question 2

multiplication rule

Answer 2

P(X and Y) = P(X)P(Y)

Question 3

Normal distr

Answer 3

mean = median = mode

Question 4

if sample size = n, normal distribution:

Answer 4

x̄~N(μ, (σ^2/n))

Question 5

standard error

Answer 5

√(σ^2/n) or σ/√n

Question 6

central limit theorem

Answer 6

if ss n>25 (large), pop doesn’t have to be normally distr. (variance = sigma sq/n)

Question 7

if sample size n<25

Answer 7

use t distribution

Question 8

small sample issues

Answer 8

misrepresentation of population = misleading data; shows greater sampling variability.