Normal Distribution
What shape is a normal distribution?
Bell‑shaped and symmetric
What is a sampling distribution?
Distribution of a statistic from all samples
What is the range of probability values?
0 to 1
What does independence mean?
One event does not affect the other
What percent of data is within 1 SD of the mean?
68%
What does the CLT say?
Sampling distribution of xˉ becomes normal for large n
What is the complement rule?
P(not A) = 1 – P(A)
State the multiplication rule for independent events.
P(A∩B)=P(A)P(B)
What is the z‑score formula?
z=x−μσ
What is the standard error formula?
σxˉ=σ/root over n
What is a sample space?
All possible outcomes
What is a random variable?
A numerical outcome of a random process
A value is 1.5 SD above the mean. What is its z‑score?
1.5
If σ = 10 and n = 25, what is SE?
2
If P(A)=0.2 and P(B)=0.3 and they are mutually exclusive, find P(A ∪ B).
0.5
If P(A)=0.5, P(B)=0.4, and P(A ∩ B)=0.2, are they independent?
Yes, because 0.5×0.4=0.2