1.7 Statistical Tests

Question 1

define ‘calculated value’

Answer 1

The value of a test statistic calculated for a particular data set

Question 2

define ‘critical value’

Answer 2

In an inferential test the value of the test statistic that must be reached to show significance.

Question 3

define degrees of freedom

Answer 3

the number of values that are free to vary given that the overall total values are known

Question 4

define levels of measurement

Answer 4

refers to the different ways of measuring items or psychological variables; the lower levels are less precise

Question 5

define ‘one-tailed test’

Answer 5

Form of test used with a directional hypothesis.

Question 6

define ‘significance’

Answer 6

A statistical term indicating that the research findings are sufficiently strong for us to accept the research hypothesis under test.

Question 7

define ‘test statistic’

Answer 7

A statistical test is used to calculate a numerical value. For each test this value has a specific name such as S for the sign test.

Question 8

define ‘two-tailed test’

Answer 8

Form of test used with a non-directional hypothesis.

Question 9

define statistical test

Answer 9

procedures for drawing logical conclusions (inferences) about the population from which the samples are drawn

Question 10

define ‘parametric’. Describe what parametric data would look like.

Answer 10

normally distributed data with small and similar standard deviations.
would produce a bell curve when plotted.
Has the best validity

Question 11

define ‘table of critical values’

Answer 11

A table that contains the numbers used to judge significance. The calculated value of the test statistic is compared to the number in the table (called the critical value) to see if the calculated value is significant.

Question 12

define ‘directional hypothesis’

Answer 12

States the direction of the predicted difference between two conditions or two groups of participants.

Question 13

define ‘hypothesis’

Answer 13

A precise and testable statement about the assumed relationship between variables. Operationalisation is a key part of making the statement testable.

Question 14

define ‘Non-directional hypothesis’

Answer 14

Predicts simply that there is a difference between two conditions or two groups of participants, without stating the direction of the difference.

Question 15

what do statistical tests do?

Answer 15

produce a calculated value

Question 16

how do we use a statistical test to determine significance

Answer 16

produce a calculated value, compare to critical value found in statistical table

Question 17

what information do we need in order to determine significance when comparing a calculated value to a critical value?

Answer 17

significance level, usually p = 0.05
one or two tailed test (directional or non-directional hypothesis respectively)
value of N or df

Question 18

in order to perform a parametric statistical test, what must the data look like?

Answer 18

have an interval or ratio level of measurement
be drawn from population with normal distribution
both samples have equal variance