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Population

Every individual or element for which data is needed.

Sample

A portion of the larger group or population selected to represent the entire population.

Census

When every individual or element in the population is counted in the recorded data.

RANDOM SAMPLE (aka UNBIASED SAMPLES)

A sample that is chosen without any member or element in the population being favored or shown preference.

BIASED SAMPLES

One or more of the members or elements of the population are favored to be chosen over the others.

Convenience Sample

Choosing members of a population that are easy to access.

Voluntary Response Sample

Members of the population volunteer to participate and be a part of the sample.

Histogram

A bar graph that has its data organized into equal intervals.

Median

The middle number in an organized set of data.

Mean

The average number in a set of data.

Mode

The number that occurs the most often in a set of data.

Measures of Central Tendency

Mean, Median, and Mode.

Measures of Variation

Measures that describe the spread values in a set of data.

Range

The difference between the greatest and least numbers in a set of data.

Quartiles

The values that separate the data into four equal subsets.

Q1 (Lower Quartile)

It divides the lower half of data into two equal parts.

Q2 (Median)

It divides all of the data into two equal parts.

Q3 (Upper Quartile)

It divides the upper half of data into two equal parts.

IQR (Interquartile Range)

The difference between the upper and lower quartiles.

Outliers

A value that is much less or much greater than the rest of the data.

Q1

Lower Quartile.

Q2

Median.

Q3

Upper Quartile.

IQR

Interquartile Range.

Simple Random Sample

Every element or member in the population has an equal chance of being chosen.

Stratified Random Sample

The population is first divided to similar, NONOVERLAPPING groups. A SRS is then taken from each group.

Systematic Random Sample

Members of the sample are chosen at a specific time or item (number) interval.

4 ways to collect data

Published newspaper, observational study, experiment, and survey

What a frequency table is used for

to tally the frequency of events before the histogram is made.

Frequency

The number of elements in a measurement class. It is written along the vertical axis.

Measurement Classes

Equal intervals which are written along the horizontal axis of the graph.

MATRIX

A rectangular arrangement of numbers in rows and columns.

DIMENSIONS OF A MATRIX

Is described as the number of rows in the matrix by the number of columns

ELEMENT

Each entry in the matrix is known as an element

POSITION OF AN ELEMENT

Is given by the element's row and column location.

Lower Outlier

Q1-1.5(IQR)

Upper Outlier

Q3+1.5(IQR)