Researc methods | infrential statistics Flashcards
(19 cards)
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What is the purpose of inferential statistics?
To generalise findings from a sample to the target population
When are results considered statistically significant?
When p < 0.05 (less than 1 in 20 chance the result is due to chance)
Which tests are used in correlational studies?
Spearman’s Rho (Ordinal) Pearson’s r (Interval) Chi-Squared (Nominal)
Which tests are used for related data in experiments?
Sign Test (Nominal) Wilcoxon Signed-Rank Test (Ordinal) Related t-test (Interval)
Which tests are used for unrelated data in experiments?
Mann-Whitney U (Ordinal) Unrelated t-test (Interval) Chi-Squared (Nominal)
What distinguishes a correlation from an experiment?
Correlation looks for a relationship or association experiment tests differences due to IV manipulation
What are the experimental designs?
Related (repeated measures or matched pairs) Unrelated (independent groups)
What are the three levels of measurement?
Nominal (categories) Ordinal (ordered ranks) Interval (equal intervals)
What is a memory aid for statistical tests?
Sign Test Wilcoxon Related t-test Chi-Squared Mann-Whitney Unrelated t-test Spearman’s Rho Pearson’s r
What are the 4 marks in naming or justifying a statistical test?
1 Name test 2 Type of test (difference or correlation) 3 Design (related or unrelated) 4 Level of measurement
How do you structure an answer when justifying a statistical test?
State name test type data relationship and level of measurement
How do you interpret significance using a critical values table?
Compare observed value to critical value note p-value and whether it’s a one-tailed or two-tailed test
What is the conclusion template for statistical significance?
The observed value (X) is [greater or less] than the critical value (Y) so we [accept or reject] the null hypothesis at p = 0.05 for a [one or two]-tailed test
How do you calculate the Sign Test?
1 Subtract conditions A minus B 2 Record signs 3 Count non-zero differences (N) 4 Find S (least frequent sign) 5 Compare S to critical value
When are results significant in the Sign Test?
If S is less than or equal to the critical value results are significant
What is the formula for degrees of freedom in Chi-Squared?
(Rows - 1) times (Columns - 1)
Which test is the only one that needs to be calculated in AQA exams?
The Sign Test
What’s a good exam tip for statistical test questions?
Sketch a stats table quickly in the exam to help guide your answers
