RESEARCH METHODS & STATISTICS
INTRODUCTION
- 0 About these materials
- 1 Introduction & Overview
FOUNDATIONS
STATISTICAL INFERENCE
- 6 Estimation & hypothesis testing
SIMPLE COMPARISONS
STUDY DESIGN & CONDUCT
STATISTICAL MODELLING
- 14 Introduction to regression models
  - Models & statistical models
  - e-lecture: Introduction to statistical modelling
EVIDENCE SYNTHESIS
- 15 Systematic Reviews
- 16 Meta Analysis
GLOSSARY
CREDITS

Test Yourself

True or False

Question 1

If the 95% confidence interval for a difference between two means contains 0 you would expect the p-value for the difference to be less than 0.05.

True False

Feedback

False

P-values and 95% confidence intervals are deterministically related. If a 95% CI contains the value that you would expect under the null hypothesis (null value) then the p-value will be >0.05.

Question

If the difference between the two sample means has a p-value less than 0.05, which of the following would be true:

Answers

Option 1

The 95% confidence interval for the difference between the two means will contain 0.

Option 2

The 95% confidence interval for the difference between the two means will exclude (not contain) 0.

Feedback

Wrong

Correct: the 95% CI will not contain the null value (zero in this example) if the p-value is less than 0.05.

Solution

Wrong (Feedback)
Correct Option (Feedback)

True or False

Question 1

Two variables are observed to have a correlation coefficient of 0.2 with 95% confidence limits of -0.15 to 0.55. We can also conclude that there is no evidence for a linear association between these two variables

True False

Feedback

True

The CI contains the null value for the correlation coefficient of 0. It also comfortably contains zero which means the p-value for a test of this correlation coefficient would be fairly large.

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