1.7 Statistical Tests Flashcards
define ‘calculated value’
The value of a test statistic calculated for a particular data set
define ‘critical value’
In an inferential test the value of the test statistic that must be reached to show significance.
define degrees of freedom
the number of values that are free to vary given that the overall total values are known
define levels of measurement
refers to the different ways of measuring items or psychological variables; the lower levels are less precise
define ‘one-tailed test’
Form of test used with a directional hypothesis.
define ‘significance’
A statistical term indicating that the research findings are sufficiently strong for us to accept the research hypothesis under test.
define ‘test statistic’
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.
define ‘two-tailed test’
Form of test used with a non-directional hypothesis.
define statistical test
procedures for drawing logical conclusions (inferences) about the population from which the samples are drawn
define ‘parametric’. Describe what parametric data would look like.
normally distributed data with small and similar standard deviations.
would produce a bell curve when plotted.
Has the best validity
define ‘table of critical values’
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.
define ‘directional hypothesis’
States the direction of the predicted difference between two conditions or two groups of participants.
define ‘hypothesis’
A precise and testable statement about the assumed relationship between variables. Operationalisation is a key part of making the statement testable.
define ‘Non-directional hypothesis’
Predicts simply that there is a difference between two conditions or two groups of participants, without stating the direction of the difference.
what do statistical tests do?
produce a calculated value
how do we use a statistical test to determine significance
produce a calculated value, compare to critical value found in statistical table
what information do we need in order to determine significance when comparing a calculated value to a critical value?
significance level, usually p = 0.05
one or two tailed test (directional or non-directional hypothesis respectively)
value of N or df
in order to perform a parametric statistical test, what must the data look like?
have an interval or ratio level of measurement
be drawn from population with normal distribution
both samples have equal variance
