Data/Sampling
The difference between discrete and continuous quantitative data
Discrete data are counted (whole numbers only), continuous data are measured (decimals / fractions)
The measure of center that locates the middle of the data (found by putting the data in order and finding the middle element)
The numerical value for the probability of something that is certain or guaranteed
100% or 1.0
The sampling method where members of the populations are assigned numbers, and then random numbers are selected
Simple random sampling
The measure of center that is found by adding all the values and dividing by the number of values
Mean
The numerical value for the probability of something that is impossible
0% or 0
The difference between nominal and ordinal data (hint: both are categorical)
Nominal data can't be ordered, and ordinal data has an inherent order to it
The distance between the first quartile and the third quartile (the measure of spread that goes with the median)
Interquartile range
Two events must be ___ for this equation to be true:
P(A&B)=P(A)*P(B)
independent
Distance from the mean, measured in standard deviations
Z-score
The sampling method in which the population is divided into groups called strata, and then a proportionate number is taken from each stratum.
Stratified sampling
The measure of spread that measures the distances all the data values to the mean
Standard deviation
Determine if the following events are independent:
P(A) = 0.5
P(B) = 0.3
P(A & B) = 0.2
Not independent
P(A) * P(B) = 0.5 * 0.3 = 0.15
0.15 != 0.20
The difference between ratio and interval data (hint: both are quantitative)
The lowest value for ratio data must be 0, while interval data can have negative values
Populations have parameters, and we estimate these by calculating ____ for samples
Statistics
In Emily's past classes, 70% of students earned an 90, 15% earned an 80, 10% earned a 70, and 5% earned a 60.
What is the expected value for students' grades in her class?
note: this is not real data
85%
0.7*90+0.15*80+0.1*70+0.5*60
63+12+7+3
85