WACE Maths Applications key terms

Data recorded in pairs, where each item gives a value for two variables, such as height and arm span, so that the relationship between the variables can be examined.

The variable used to predict or account for changes in another variable; it is plotted on the horizontal axis of a scatterplot.

The variable whose value is being predicted or explained; it is plotted on the vertical axis of a scatterplot.

A graph of paired data drawn as points on a grid, used to reveal the direction, strength and shape of any association between two variables.

A number between negative one and positive one that measures the strength and direction of a straight-line association between two variables; values near zero mean a weak linear relationship.

A situation where a change in one variable directly produces a change in another; strong correlation alone does not establish it, since a third factor may influence both.

A hidden third factor that influences both variables being compared, which can create the appearance of a direct relationship between them.

The straight line fitted to bivariate data that makes the sum of squared vertical distances from the points as small as possible; used for prediction.

Using a fitted line or model to predict a value that lies inside the range of the observed data, which is generally a reliable use of the model.

Predicting beyond the range of the observed data using a fitted model; this is risky because the pattern may not continue outside the recorded values.

A data value that lies well away from the general pattern of the other observations and may distort summary statistics or a line of best fit.

The sum of all data values divided by the number of values; a measure of centre affected strongly by unusually large or small observations.

The middle value of an ordered data set, or the average of the two middle values when the count is even; it resists distortion by outliers.

A measure of how spread out data values are around the mean, roughly representing a typical distance of a value from the mean.

The average of the squared distances of data values from the mean; its square root is the standard deviation.

The difference between the upper and lower quartiles, giving the spread of the middle half of the data and ignoring the extreme quarters.

The set consisting of the minimum, lower quartile, median, upper quartile and maximum, used to describe a data set and to draw a boxplot.

A diagram showing the five-number summary as a box from lower to upper quartile with a line at the median and whiskers to the extremes.

A symmetric bell-shaped distribution of continuous data in which most values cluster near the mean and become rarer further away in either direction.

For normally distributed data, about 68 percent of values lie within one standard deviation of the mean, about 95 percent within two, and about 99.7 percent within three.

The number of standard deviations a value lies above or below the mean, found by subtracting the mean and dividing by the standard deviation; also called a z-score.

A number describing how far a seasonally affected value typically sits above or below the trend, expressed as a percentage or a proportion of the trend value.

A set of values recorded at regular time intervals, such as monthly sales figures, analysed to reveal trend and seasonal patterns.

A line fitted to time series data that shows the general long-term direction of the values after short-term fluctuations are smoothed out.

A smoothing method that replaces each value with the average of a fixed number of neighbouring values, reducing short-term fluctuations so the trend is clearer.

Interest calculated only on the original amount invested or borrowed, using the formula interest equals principal times rate times time, with no interest on interest.

Interest calculated on the current balance, so that interest earned in earlier periods also earns interest in later periods, producing growth faster than simple interest.

The original amount of money invested or borrowed before any interest is added or repaid.

The amount an investment or loan will be worth after interest has been applied for a given time, including the original principal.

The amount that must be invested now, at a given interest rate, to reach a required future amount; found by reversing compound interest growth.

The stated annual interest rate before any adjustment for how often interest is compounded within the year.

The true annual growth rate once compounding within the year is taken into account; it exceeds the nominal rate when compounding happens more than once a year.

A series of equal payments made at regular intervals, such as a regular deposit into a savings account or a loan repayment schedule.

A rule that generates each value in a sequence from one or more earlier values, commonly used to model compounding balances or regular deposits.

A collection of vertices joined by edges, used to model networks such as roads between towns or friendships between people.

A point or node in a graph, representing an object or location such as a town, person or junction.

A link connecting two vertices in a graph, which may be weighted to represent a distance, cost or time.

The number of edges meeting at a vertex; in a graph of a network it counts the direct connections that vertex has.

A graph in which each edge carries a numerical value, such as a distance or cost, so that routes can be compared and optimised.

The route between two vertices whose total edge weight is as small as possible, often found by comparing accumulated weights step by step.

In a project network, the longest chain of dependent activities from start to finish, which determines the minimum possible completion time.

The amount by which a non-critical activity can be delayed without delaying the whole project; it is zero for activities on the critical path.

A route through a graph that uses every edge exactly once; such a trail exists only when exactly zero or two vertices have an odd degree.