Week 10-

Question 1

Regression

Answer 1

The regression method summarizes the relationship between two variables. It is used to estimate the average of one variable for a particular value (or range of values) of the other variable, while noting that individual values will vary around this average.

Question 2

Responsevariable:

Answer 2

Variable we wish to learn about. Also called the outcome or dependent variable.
Notation: y

Question 3

Explanatory variable:

Answer 3

Variable that is thought to explain the changes we see in the response variable. Also called the independent variable.

Question 4

(Properties of correlation coefficient )

Value doesn’t depend onwhich variable is the
response variable orwhich is the explanatory
variable:

Answer 4

IfIswitchXandY, then correlation(r) doesn’t change.

Question 5

(Properties of correlation coefficient )

Value doesn’t depend onunits ofmeasurement

Answer 5

IfImeasure ininches insteadof centimeters,then correlation (r)doesn’t change.

Question 6

Outlierswilloftenchangethevalueofthecorrelation.

Answer 6

– Ifthey areon the samepatternasthe restofthe data,they willtypicallystrengthen the correlation.
– Ifthey areoffthe patternofthe restofthe data,they willtypicallyweaken the correlation.

Question 7

Residual:

Answer 7

Verticaldistancebetween the regressionlineandaparticulardatapoint.