bivariate data

What do you do on the calculator to calculate bivariate data

Home - stats - 2 variable - rev results - y=a +bx

What do you do when calculating PMCC?

Type the raw data into the calculator

What do you do when calculating SRCC?

Rank the data separately and type the ranks into the calculator

What do you do for the regression equation?

Type the raw data into the calculator and fill in A and B as shown on the calculator screen

What is regression?

The equation of the line of best fit

What is a residual?

The difference between the observed value of the dependent variable and the expected value (use ROME as a way of rembering this)

What is an outlier?

A point that has a large residual value

What is

Pearsons

Product

Moment

Correlation

Cooefficient

(PMCC)

A measure of the linear correlation of two variables, X and Y. It has a value between +1 and - 1 where :

• 1 is total positive correlation

• 0 is no linear correlation

• -1 is total negative correlation

What is

Spearmans

Rank

Correlation

Cooefficient

(SRCC)

Assesses how well the relationship between two variables can be described in a monotonic (has a generally increasing/decreasing trend) system.

(Data with a trend that is not necessarily linear, but can be)

What is the standard answer for the y intercept?

When ‘x variable’ is ‘0 units: the ‘y variable: is a ‘unit’

What is the standard answer for the gradient?

As ‘ x variable ‘ increases by ‘1 unit ‘the ‘y variable’ increases/decreases by ‘b units ‘

What is extrapolation?

Manking an estimation outside of the range of the data set

What is interpolation?

Making an estimation inside of the range of the data set

What is PMCC a test for?

A linear relationship

What must PMCC have?

• A bivariate normal

• A random sample

What does SRCC test for?

A ranked association

What does the sample have to be in SRCC?

Random

When MUST you choose SRCC?

• Population dorsn’t follow a bivariate normal distribution

• Ranked data

• Data doesn’t seem to be linear

• The data is qualitative