chapter 4 statistics flashcards

Exploring variable relationships

Looking at two or more things to see if changing one affects or connects to the other.

Response

The main outcome or result you are measuring. It changes based on other factors (also called the dependent variable).

Explanatory

The factor you think causes or explains a change in the result (also called the independent variable).

Quantitative

Information made of numbers that you can measure or count, like height, age, or speed.

Qualitative

Information made of descriptions or labels rather than numbers, like colors, names, or feelings.

Conditional percentages

The percentage of a group that fits a specific condition, calculated by looking at just one subgroup instead of the whole total.

Scatterplots

A graph with points plotted on a grid to show how two numerical variables are related.

Form of scatterplots

The overall shape made by the points on the graph, such as a straight line, a curve, or no pattern at all.

Direction of scatterplots

The general trend of the points, showing whether the graph goes up or down as you move from left to right.

Strength of scatterplots

How closely the plotted points follow a clear line or pattern, showing how strong the link between the variables is.

Negative association

A relationship where as one value goes up, the other value goes down (moving in opposite directions).

Positive association

A relationship where as one value goes up, the other value also goes up (moving in the same direction).

Correlation coefficient (r)

A single number between -1 and +1 that tells you both the direction and how strong a straight-line relationship is.

Standard deviation

A number that shows how spread out or scattered data points are from their average value.

Product

The result you get when you multiply two or more numbers together.

Correlation vs causation

Just because two things happen together (correlation) does not mean one caused the other to happen (causation).

Spurious correlation

A fake or misleading connection between two things that appears related only because of random chance or a hidden third factor.

Residuals

The gap or difference between the actual value you measured and the value predicted by a line of best fit.

Least squares regression line

The single best mathematical line drawn through a scatterplot that makes the overall distance to all data points as small as possible.

Line of best fit

A straight line drawn through data points on a scatterplot to show the general trend and help make predictions.

Slope of the least squares regression line

A number showing how much the predicted outcome changes for every 1-unit increase in the starting variable.

Predict y from x

Using a known starting number (x) in a formula to estimate what the unknown result (y) will be.