Permutations: # of ways to select n elements in r places: nPr

Combination: order doesnt matter in selection

Hypothesis testing: to decide if there is enough evidence to reject a hypothesis.

Null hypothesis: baseline assumption where there is no effect or difference

Significance value: (α) is the threshold for determining whether the observed data is extreme enough to reject the null hypothesis, commonly set at 0.05.

Type 1 error: rejecting null hypothesis while it is true in reality.

Type 2 error: accepting null hypothesis while it is false in reality.

2 tailed question:

checks for the possibility of an effect in both directions, meaning it tests whether a parameter is significantly greater than or less than a certain value.

1 tailed question:

checks for an effect in only one direction, either greater than or less than a certain value.

Point estimation:

estimate a parameter(population variable) from statistic (sample variable).

Upper bound:

Point estimate + margin of error

Lower bound:

Point estimate - margin of error