Inferential Statistics Flashcards

1
Q

What are the characteristics of research study?

A
  1. Formulate. Research question/study design/generate hypothesis
  2. Patient recruitment, data collection and entry
  3. Data analysis
  4. Descriptive statistics
  5. Inferential statistics
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2
Q

What are the 2 types of measurement?

A

Numerical and categorical

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3
Q

What must you decide before undertaking before undertaking any analysis?

A
  • are the data evenly distributed?

- is it parametric or non-parametric?

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4
Q

What are the 4 conditions that must be fulfilled to undertake parametric test?

A
  • data must be interval/ratio
  • subjects must be randomly selected
  • data must be normally distributed
  • variation in results from each condition should be similar
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5
Q

What is descriptive data analysis?

A
  • Subjects usually only measured once

- establishes only associations between variables

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6
Q

What is experimental data analysis?

A
  • subjects measured before and after a treatment

- can establish causality

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7
Q

How do you establish a p-value?

A
  • done before the start of the study

- use a power calculation to determine sample size needed

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8
Q

What are the 2 types of study design?

A

Experimental and correlational

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9
Q

What is Chi-square test?

A
  • considers the distribution of actual data and what would be expected
  • DV is categorical
  • based on frequency counts
  • minimum response size = 80% of cells must contain a minimum expected frequency of 5 and no empty cells
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10
Q

What is considered a weak r value?

A

Between 0.1-0.4

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11
Q

What is considered a moderate r value?

A

0.5-0.7

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12
Q

What is considered a strong r value?

A

0.8-1.0

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13
Q

What is a correlational coefficient?

A
  • a numerical description of this tendency
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14
Q

What does a -1 correlation coefficient mean?

A

Perfect negative correlation

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15
Q

What does a +1 correlation coefficient mean?

A

Perfect positive correlation

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16
Q

What does a correlation coefficient of 0 mean?

A

No relationship

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17
Q

What are he conditions for correlations?

A

Need paired sets of measurements from either:
- 2 different sets of measurements from the same sample
- same set of measurements from matched pairs of individuals
- same set of measurements from same individuals at 2 different points in time
A linear relationship

18
Q

Which statistical test do you use for a correlational parametric data?

A

Pearson product moment

19
Q

What are the characteristics of Pearson product moment?

A
  • all data is continuous
  • data is normal
  • relationship is linear
20
Q

What test do you use for a correlational non parametric data?

A

Spearman rank correlation

21
Q

What are the characteristics of Spearman rank correlation?

A
  • both variables from the same sample or matched pairs

- either ordinal data or skewed continuous data

22
Q

How can you tell is a result is significant?

A
  • p>0.05 = not statistically significant
23
Q

What is the confidence interval (CI)?

A
  • the range of values within which it is reasonably certain that the population value lies
  • concerned with precision, how much the sample estimates is likely to differ on average from the true population value
  • can be calculated for different tests
  • estimate the effect of treatment
  • width of the CI gives an indication of the precision of the estimate
  • if statistically significant the CI won’t include the null hypothesis
24
Q

Which test do you use for 2 groups and parametric tests?

A

Unrelated t test

25
What tests are used for between group comparisons?
- unrelated t test - Mann-Whitney U test - fishers exact test - one-way ANOVA - kruskall Wallis - Chi-squared test
26
What tests do you use for within group comparisons (repeated measures)?
- related t test - wilcoxon signed rank test - McNemar
27
What statistical test do you use for 2 groups and non-parametric test?
Mann-Whitney U test
28
What statistical test do you use for 2 groups and categorical data?
Fishers exact test
29
What statistical test do you use for >2 groups and parametric tests?
One way ANOVA
30
What statistical test do you use for >2 groups and non-parametric tests?
Kruskall Wallis
31
What statistical test do you use for >2 groups and categorical data?
Chi-square test
32
What statistical test do you use for 2 measures and parametric tests?
Related t test
33
What statistical test do you use for 2 measures and non-parametric test?
Wilcoxon signed rank test
34
What statistical test do you use for 2 measures and categorical data?
McNemar
35
What are the characteristics of unrelated t test?
- compares the means between groups | - looks at descriptive data: normal distribution, continuous scale, unpaired data, standard deviations should be similar
36
What are the characteristics of Mann-Whitney U test?
- non-parametric equivalent of t test - compares ranked scores for each group - independent groups - ordinal or interval data - small or unequal samples
37
What are the characteristics of one way ANOVA?
- single dependent variable - continuous/interval scale - normal data with similar standard deviation
38
What are the characteristics of Kruskal-Wallis test?
- interval or ordinal | - group differences in the mean rank values
39
What are the characteristics of related t test?
- within group comparisons - repeated measures with same individual - measurements from matched (demographically) pairs
40
What are the characteristics of Wilcoxon signed rank test?
- data for each group related matched pairs or repeated measures - continuous or ordinal scale with at least 4 points
41
When testing an idea or hypothesis what do you need to do?
- a hypothesis must be devised and stated - a researcher project must be designed which tests the hypothesis - results must be analysed with descriptive and statistical test