Peer-graded Assignment: Open Science – Romantic Comedy Feud: JR vs MR (#3163)

Author(s) Created: 02/25/2017 05:24 AM (PT) Adrian Zahn (Saarland University) - [email protected] Public: 02/26/2017 12:14 AM (PT)

1) What's the main question being asked or hypothesis being tested in this study? Both Julia Roberts and Meg Ryan starred in numerous romantic comedy movies (rom coms) during the 1990s and early 2000s and are considered “rom com it girls”. But while Mag Ryan’s career seems to have stagnated ever since, Julia Robert’s star continued to shine. The purpose of this study is to investigate whether the differential career trajectories of the two actresses are also reflected in the quality of some of their early works, namely the average IMDB ratings of their rom com movies. The study tests the hypothesis that rom coms starring Julia Roberts are, on average, more popular than rom coms that feature Meg Ryan.

2) Describe the key dependent variable(s) specifying how they will be measured. For the purpose of this study, IMDB ratings are chosen as a measure of movie popularity.

3) How many and which conditions will participants be assigned to? Two groups: Rom coms starring Julia Roberts vs rom coms starring Meg Ryan

4) Specify exactly which analyses you will conduct to examine the main question/hypothesis. To test the hypothesis that Julia Roberts rom coms receive, on average, a more favorable IMDB rating, a one-tailed t test for independent means is applied to the data. The alpha level is set to .05 in order to keep the long-term probability of falsely accepting the alternative hypothesis at a reasonably low level. In addition, a “one-tailed” Bayesian t test is conducted. The prior distribution is set as a half normal with SD = 0.80 reflecting the belief that smaller positive effects of casting Julia Roberts are slightly more likely than larger effects.

5) Any secondary analyses?

6) 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. It is assumed that the cast can have a medium-sized effect (d = 0.50) on the IMDB rating of a movie at best. Opting for 80% power and using the conventional α = .05, an a priori power analysis using G*Power suggests a total required sample size of N = 102. Unfortunately, the sample size for this quasi-experimental study is capped by the maximum number of movies that qualify for inclusion in one of the two groups, i.e. by the total number of rom coms that feature either Julia Roberts or Meg Ryan. An IMDB search for currently released feature films which include Meg Ryan and were tagged as both comedy and romance resulted in 17 hits. A search with equivalent criteria for Meg Ryan movies resulted in 15 hits. Thus, a total of 32 observations is available for statistical analyses which falls short of the suggested sample size by 70 observations.

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

8) Have any data been collected for this study already? No, no data have been collected for this study yet

Available at https://aspredicted.org/h8wb9.pdf Version of AsPredicted Questions: 1.05 (Permanently archived at http://web.archive.org/web/*/https://aspredicted.org/h8wb9.pdf)