Exercise: Testing the interaction in two-by-two ANOVA

Anchoring and adjustment

Items and anchor values (Jacowitz and Kahneman 1995)

How tall is the largest coast redwood in the world? [20, 168m]
How many member states belong to the United Nations? [14, 127 members]
How much km/h is the maximum speed of a house cat? [11, 48km/h]

Research question

Does time pressure (respond within 7s) increase the anchor effect?

Suggest a minimum relevant effect

Go to https://apps.mathpsy.uni-tuebingen.de/fw/pars2eta/
Fix the parameters of the ANOVA model

Some background

Open anchoring quest (Röseler et al. 2022), https://osf.io/ygnvb/

Plan the study

Pick one of the three items
Parameter recovery
- Make a data frame for the two-by-two design
- With the parameter values determined before, simulate responses
- Re-estimate the parameters
Power simulation
- Calculate the sample size necessary to detect the time-pressure effect

Bonus task: Verify the plausibility of your model

Download the raw data from the open anchoring quest project
Estimate \sigma and compare it to your value

References

Jacowitz, K. E., and D. Kahneman. 1995. “Measures of Anchoring in Estimation Tasks.” Personality and Social Psychology Bulletin 21 (11): 1161–66. https://doi.org/10.1177/01461672952111004.

Röseler, L., L. Weber, K. A. C. Helgerth, E. Stich, M. Günther, P. Tegethoff, F. S. Wagner, et al. 2022. “OpAQ: Open Anchoring Quest, Version 1.1.50.97.” https://doi.org/10.17605/OSF.IO/YGNVB.

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