# Unit 2 Vocabulary

### average

an alternative word for mean

### balancing point

the point on a number line where the data distribution is balanced

### bell-shaped

the bell shape that is created on a graph of a normal distribution

### bias

the act of favoring one outcome over another

### boxplot

A special type of diagram showing Quartiles 1, 2 and 3 (where the data can be split into quarters) in a box, with lines extending to the lowest and highest values

### chance

the possibility that something will happen

### compound probabilities

AND/OR probabilities; the likeliness of two independent events occurring

### deviation

the act of departing from an established course or accepted standard

### Empirical Rule

in a normal data set, virtually every piece of data will fall within three standard deviations of the mean

### event

a set of possible outcomes resulting from a particular experiment

### first quartile (Q1)

a number for which 25% of the data is less than that number

### five-number summary

a set of numbers that provides information about a dataset; consist of minimum, first quartile, median, third quartile, and maximum

### independence

if one event doesn't affect the outcome of another event

### interquartile range (IQR)

the range from Quartile 1 to Quartile 3

### maximum

the largest value

### mean

a calculated "central" value of a set of numbers, where you add the numbers and divide by how many there are

### mean of absolute deviations (MAD)

the average distance between each data value and the mean

### measures of central tendency (or center)

a central or typical value for a probability distribution

### measures of variability (or spread)

how far away the data points tend to fall from the center

### median

the middle value in a group of ordered observations

### merge

to come together or combine

### minimum

the smallest value

### model

a way of representing real world situations so that predictions can be made

### normal curve

curve or the graph is the common type of distribution for a variable

### normal distribution

an arrangement of a data set in which most values cluster in the middle of the range

### percentage

parts per 100; for each hundred; a fraction whose denominator (bottom) is 100

### probability

how likely it is that some event will occur

### proportion

when two ratios (or fractions) are equal

### quantiles

a term that can be used in place of percentiles because they represent a *quantity* of data that is lower than that value

### quartiles

the values that divide a list of numbers into quarters

### randomness

happening by chance; not able to be predicted

### range

the largest value minus the smallest value

### rebuttal

an opposing argument or debate

### representation

the form in which data is stored, processed, and transmitted

### sample proportion

the fraction of samples which were successes

### shuffle

rearrange so as to occupy different random positions or to be in a different random order

### simulation

a way of creating random events that are close to real-life situations without actually doing them

### standard deviation (SD)

a measure of how spread out numbers are; the square root of the variance

### standardized score

another name for z-score

### subset

a set of which all the variables are contained in another set.

### third quartile (Q3)

a number for which 75% of the data is less than that number

### typical

“mean” or “average”; expected values

### with replacement

when a population element can be selected more than one time

### without replacement

when a population element can be selected only one time

### z-score

tells us how many standard deviations away from the mean an observation is