'Pretest for text-picture validation study'
(AsPredicted #61,019)
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1) Have any data been collected for this study already?
No, no data have been collected for this study yet.

2) What's the main question being asked or hypothesis being tested in this study?
The aim of this pre-study is to create a stimulus set of about 170 sentence pairs which do not differ in their probability of occurrence.

3) Describe the key dependent variable(s) specifying how they will be measured.
Probability of occurrence: Participants have to rate the probability of occurrence for each sentence on a Likert scale ranging from 1 (not at all likely) to 7 (very likely).

4) How many and which conditions will participants be assigned to?
Two between-subjects conditions: Every condition includes one sentence of the sentence pairs. Subjects will be randomly assigned to one of the two conditions. This means they have to rate about 170 sentences (plus improbable filler sentences) regarding the probability of occurrence in this pre-study.

5) Specify exactly which analyses you will conduct to examine the main question/hypothesis.
For each sentence pair a between subject two-sided t-test will be conducted separately.

In addition, the mean difference in probability of occurrence ratings for each sentence pair will be calculated. Based on this difference, an outlier-analysis will be conducted. The outlier-analysis will be based on the interquartile range and z-scores. Sentence pairs with a mean difference in probability of occurrence > Q 3 + 1.5 * interquartile range or < Q1 – 1.5 * interquartile range or with z-scores >|2.5| will be defined as outliers.

Moreover, the sentences used in the main study should be rated as rather probable in the pre-study. Therefore, sentences with mean ratings below 4 will be analysed further and eventually changed or removed from the stimulus set.

Finally, the mean rating of all first sentences and the mean rating of all second sentences of the sentence pairs will the calculated. Based on those two means, a between subject two-sided t-test will be calculated.

6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations.
Participants who do not agree to have their data processed will be deleted.

We will exclude participants who incorrectly answer at least three of our five attention check questions (e.g. “Please rate this statement with 3”).

If participants require on average less than one second per response, their response behaviour will further be analysed. If there are further indicators of unclean processing (e.g. a SD across all ratings which is 2SD lower than that of the other participants), the participant will be excluded.

Furthermore, participants who rate the improbable filler sentences on average as probable (mean above 4) will be excluded as well.

7) How many observations will be collected or what will determine sample size?
No need to justify decision, but be precise about exactly how the number will be determined.
Based on a power-analysis conducted with g-power for a two-sided t-test (d = 0.5, α = 0.05, 1-β = 0.8) 128 participants are required. Due to possible drop-out 140 participants will be assessed.

8) Anything else you would like to pre-register?
(e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?)