Linear Stats

Question 1

primarily concerned with finding out whether a relationship exists

Answer 1

Correlation

Question 2

Correlation determines the _______ and ______

Answer 2

magnitude and direction

Question 3

are attempts to find the extent to which two or more variables are related.

Answer 3

correlational studies

Question 4

TRUE OR FALSE: in a correlational study, no variables are manipulated as in an experiment

Answer 4

True

Question 5

TRUE OR FALSE: the researcher measures NATURALLY occurring events, behaviors, or personality characteristics

Answer 5

TRUE

Question 5

The simplest correlational study involves?

Answer 5

obtaining a pair of observations or measures on two different variables from a number of individuals

Question 6

Possible outcomes for correlation?

Answer 6

Perfect Positive, Zero, Perfect Negative

Question 7

How would you describe the shape or the pattern of the data points

Answer 7

linear pattern

Question 8

When one variable moves a certain direction, the other tends to move in the same or opposite direction.

Answer 8

COVARIANCE

Question 9

Positive or Negative Correlation: people who do more revisions get higher exam results

Answer 9

Positive correlation

Question 10

Positive or Negative Correlation: When more jabs are given, the number of peple with flu falls

Answer 10

Negative correlation

Question 11

is one of a family of statistical measures used to analyse the linear relationship between two variables

Answer 11

Covariance

Question 12

provides the DIRECTION (positive, negative, near zero) of the linear relationship between two variables

Answer 12

Covariance

Question 13

provides DIRECTION and STRENGTH

Answer 13

Correlation

Question 14

result has no upper or lower bound and its size is dependent on the scale of the variables

Answer 14

Covariance

Question 15

is always between -1 and +1 and its scale is independent of the scale of the variables themselves.

Answer 15

Correlation

Question 16

Example of why covariance is not standardized:

Answer 16

we can measure the covariance of two variables that are measured in meters, however, if we convert the same values to centimetres, we get the same relationship but with a completely different covariance value.

Question 16

Which is standardized? Covariance or Correlation?

Answer 16

Correlation

Question 17

What is the standardised covariance used?

Answer 17

Pearson’s correlation coefficient (or “r/R”)

Question 18

Range of Pearson R?

Answer 18

-1.0 to + 1.0

Question 19

What do the values Zero, Greater than zero, and less than zero indicate?

Answer 19

❏ A value of 0 indicates that there is no association between the two variables

❏ A value greater than 0 indicates a positive association; that is,
as the value of one variable increases, so does the value of the other variable.

❏ A value less than 0 indicates a negative association; that is, as
the value of one variable increases, the value of the other variable decreases (inverse correlation)

Question 20

The ______ the association of the two variables, the _______ the Pearson correlation coefficient, r, will be to either +1 or -1 depending on whether the relationship is positive or negative, respectively.

Answer 20

Stronger ; closer

Question 21

Achieving a value of +1 or -1 means that all your data points are included on the line of ______ _____ – there are no data points that show any variation away from this line.

Answer 21

Best fit

Question 22

How can we determine the strength of association based on the Pearson
correlation coefficient?

Answer 22

❏ Values for r between +1 and -1 (for example, r = 0.8 or -0.4) indicate that there is variation around the line of best fit

❏ The closer the value of r to 0 the greater the variation around the line of best fit.

Question 23

Before going crazy computing correlations look at a ________ of your data. What pattern (if any) does it exhibit?

Answer 23

Scatterplot

Question 24

TRUE OR FALSE: Correlation is NOT causation

Answer 24

TRUE

Question 25

TRUE OR FALSE: Correlation is only applicable to LINEAR relationships.

Answer 25

TRUE

Question 26

TRUE OR FALSE: Correlation strength necessarily means that the correlation is statistically significant; related to sample size.

Answer 26

FALSE

Question 27

Non-Parametric test used:

Answer 27

Spearman rank order correlation coefficient (r rho)

Question 28

employed with interval or ratio scaled variables

Answer 28

Pearson product moment correlation coefficient ( r )

Question 29

employed with ordered or ranked data.

Answer 29

Spearman rank order correlation coefficient (r rho)

Question 30

Two sets of measurements are obtained on the same individuals or on pairs of individuals who are matched on some basis

Answer 30

Correlation

Question 31

The values of the correlation coefficients vary between +1.00 and –1.00. Both of these extremes represent ________ relationships between the variables, and 0.00 represents the _______ of a relationship.

Answer 31

Perfect ; Absence

Question 32

means that individuals obtaining high scores on one variable tend to obtain high scores on a second variable. The converse is also true, i.e., individuals scoring low on one variable tend to score low on a second variable.

Answer 32

Positive Relationship

Question 33

means that individuals scoring low on one variable tend to score high on a second variable. Conversely, individuals scoring high on one variable tend to score low on a second variable.

Answer 33

Negative Relationship

Question 34

Assumptions:

Answer 34

1.) there must be related pairs of scores that come from one subject 2.) RS between 2 variables must be linear 3.) Variables should be measured at least at the interval ( x and y are scale/continuous ) 4.) variability of scores on the Y variable should remain constant at all values of the X variable. This assumption is called homoscedasticity.

Question 35

There is gradual spreading and has unequal variability

Answer 35

Heteroskedasticity

Question 36

How do I report the output of a Pearson product-moment correlation?

Answer 36

Pdf

Question 37

how to solve df

Answer 37

Minus 2

Question 38

How do I report the output of a Pearson product-moment correlation?

Answer 38

“A Pearson product-moment correlation was run to determine the relationship between height and distance jumped in a long jump. There was a strong, positive correlation between height and distance jumped, which was statistically significant (r = .706, n = 14, p = .005).” “A Pearson correlation coefficient was computed to assess the linear relationship between hours studied and exam score. There was a positive correlation between the two variables, r(38) = .48, p = .002.”

Question 39

If you take the correlation cofficient r and square it you get the_______ __ _______ (__). This is a statistical measure of the proportion of variance in one variable that is explained by the other variable

Answer 39

coefficient of determination (R2 ) OR R2 = Explained variation / Total variation

Question 41

In the example above r = 0.984, so R2 = 0.968. This suggests that

Answer 41

jump height accounts for 96.8% of the variance in explosive leg power.