DS Skills Lab 08
Interpreting & Reporting Results
Dr Danielle Evans
24 Nov 2023
Overview
Results Write-up
Results Section:
Descriptive Statistics
Statistical Analysis
Main Results
Reporting with Tables
Getting Help
KahootR
so for today's session we're going to be focusing on how we can actually report the results of our statistical analyses
breaking it down into 3 parts
so this session will help you use the info in the set analysis that we looked at last week
and hopefully by the end of the session you'll have a greater understanding of how you can write up a results section for your dev psych report
i might monitor the chat for responses later so please dont message me with anything private
we have quite a bit to zoom through today
Results Write-up
The results section should be a clear summary of what your study actually found
For most models, you can think of this section as being made up of 3 components:
Descriptive Statistics
Statistical Analysis
Main Results
You can approach your results write-up by thinking about what questions each of these components need to answer...
OOPS! You don't need to explain any statistical concepts, you can assume your reader knows stats!
Writing up Results: Descriptives
Questions to answer in this section:
How did participants score on each measure?
I.e., what were the:
Means
SDs/Confidence intervals etc.
Ranges
OOPS! You should NOT include any variable names in your write-up - no one else knows what your data looks like or what your variables are called!
Finding the Values: Descriptives
set analysis might have a similar table to this one, same as tap
in the models today, im looking at whether teaching evaluation scores can be predicted from instructor beauty, and kindness
in this study, we have teach evals as our outcome
beauty and kindness as our predictors
and a bunch of summary stats about those variables
need to look at the original measures to contextualise these values, and you need to know what a high score means
1-10
1-5
1-5
higher vals = better teaching, higher beauty, and higher kindness
Build-a-Summary!
- Using what you know and the examples given in the app, try arranging the 'descriptives' sentences to build-a-summary!
01:45
Writing up Results: Statistical Analysis
Questions to answer in this section:
What model(s) did you fit?
Which model was better?
What assumptions you checked, and the outcome of those checks?
How well the model fits your data?
TIP! You shouldn't include the plots of the assumption checks - just report what you checked & the conclusions/outcome of them!
Finding the Values: Model Comparison
Finding the Values: Assumptions
- Plots & casewise diagnostics (standardised residuals, Cook's distance)
name & description of plots are given in the beast of bias section in discovr_08
heteroscedasticity & linearity
the first two: residual plots The predicted values from the model (x-axis) against the residuals (y-axis). Use this plot to look for linearity and homoscedasticity.
The predicted values from the model (x-axis) against the square root of the standardized residuals (y-axis). This is a variant of plot 1 and is used to look for linearity and homoscedasticity.
normality of residuals
A Q-Q plot of the standardized residuals. Use this plot to look for normality of residuals.
outliers and influential cases
The case number (x-axis) against the Cook’s distance (y-axis). This plot can help to identify influential cases (cases with large values for Cook’s distance).
Cook’s distance to identify influential cases and standardized residuals to check for outliers
- No, the appropriate proportion of cases have standardized residuals in the expected range and no case has a value grossly exceeding 3.
Finding the Values: Model Fit
Build-a-Model!
- Using what you know and the examples given in the app, try arranging the 'statistical analysis' sentences to build-a-model!
02:00
Writing up Results: Main Results
Questions to answer in this section:
What were the effects of your predictors?
What do the effects mean in plain terms?
What predictor(s) had the strongest effects?
TIP! You should report unstandardized bs because they're easier to interpret, but it's also useful to report the standardized Bs to compare predictors!
Finding the Values: Parameters (bs)
Finding the Values: Std. Betas (Bs)
Build-a-Results!
- Using what you know and the examples given in the app, try arranging the 'main results' sentences to build-a-results!
01:45
Reporting with Tables
Often when using linear models with multiple predictors we display the information in a table:
You should refer to this table in your write-up
Guide your reader to it, don't let it be a complete surprise!
- 'Table 1 shows the model parameters for predictors of.....'
- Including a table is largely a personal preference - it is not an assessment requirement, and your results section should make sense without it
NOTE! You should create any tables manually, you should NOT copy and paste the tables directly from the set analysis - they need pretty APA formatting!
Build-a-Results-Section!
So putting it all together, you should have something that includes the following:
Descriptive statistics
- Means, SDs, CIs, ranges etc for your predictors and outcome
- Tip: any participant info should be in your method section!
Statistical analysis
- Describe what model(s) you've fit to your data (use formal language NOT code language!)
- Which model was the better one and how you've come to that conclusion
- Describe how well your model fits your data
- Describe your assumption checks & the outcome of those checks
Main results
- The main results from your model (bs)
- Include a plain language summary of those relationships - contextualize what they mean based on the scales used
- Include standardised Bs to compare the importance of your predictors
Getting Help
The tutors on this module are offering drop-ins in Weeks 9 and 10 to answer questions about writing up your results section, using the Set Analysis
They cannot answer questions about the rest of the report - for that you should attend a help session hosted by one of the Developmental tutors
To see one of the tutors on this module, you can book a drop-in using the R Help Desk
The TAP grades aren't due to be released before the dev psych lab report deadline; if there are any components of the linear model that you're stuck with - PLEASE ASK US FOR HELP!!!!!
Andy's Lab Report Guide will help too!