Description:
Two news stories caught my eye related to physics (Di Falco, Ploschner, & Krauss, 2010). In the first headline (November 2010) the Daily Mirror (a UK newspaper) reported Scientists make Harry Potter's ‘invisible cloak'. I'm not really a Harry Potter aficionado, so it wasn't his mention that caught my attention, but the idea of being able to don a cloak that would render me invisible and able to get up to mischief. That idea was very exciting indeed; where could I buy one? By February 2011 the same newspaper was reporting on a different piece of research (Chen et al., 2011) with a similarly exaggerated headline: Harry Potter style „Invisible Clock“ built by scientists. Needless to say, scientists hadn't actually made Harry Potter's cloak of invisibility or anything close to it, but never let that get in the way of a headline. What Chen et al. had made wasn't so much a 'cloak' of invisibility as a `calcite lump' of invisibility. This lump could hide small objects (centimetres and millimetres in scale): you could conceal my brain but little else. Nevertheless, with a suitably large piece of calcite in tow, I could theoretically hide my whole body (although people might get suspicious of the apparently autonomous block of calcite manoeuvring itself around the room on a trolley). Di Falco et al. had created a flexible material (Metaflex) with optical properties that meant that if you layered it up you might be able to create something around which light would bend. Not exactly a cloak in the clothing sense of the word, but easier to wear than, say, a slab of calcite. Although the newspapers overstated the case a little, these are exciting pieces of research that bring the possibility of a cloak of invisibility closer to a reality. I imagine a future in which we have some cloaks of invisibility to test out. Given my slightly mischievous streak, the future me is interested in the effect that wearing a cloak of invisibility has on the tendency for mischief. Let's imagine that we had collected the cloak of invisibility data using a repeated-measures design: we might have recorded everyone's natural level of mischievous acts in a week, then given them an invisibility cloak and counted the number of mischievous acts in the following week.

Variables:

• No_Cloak: How many mischievous acts did participants perform in a week (natural level; baseline)?
• Cloak: How many mischievous acts did they perform during a week where they wore a cloak of invisibility?

Reference:
Field, A. P. (2017). Discovering Statistics Using IBM SPSS Statistics (5th ed.). Sage. [Fictional data set]
Di Falco, A., Ploschner, M., & Krauss, T. F. (2010). Flexible metamaterials at visible wavelengths. New Journal of Physics, 12(11), 113006. https://doi.org/10.1088/1367-2630/12/11/113006 [source of inspiration]
Chen, X., Luo, Y., Zhang, J., Jiang, K., Pendry, J. B., & Zhang, S. (2011). Macroscopic invisibility cloaking of visible light. Nature Communications, 2(1), 176. https://doi.org/10.1038/ncomms1176 [source of inspiration]
The data set was constructed by Andy Field who therefore owns the copyright. Andy Field generously agreed that we can include the data set in the jamovi data library. This data set is also publicly available on the website that accompanies Andy Field`s book, https://edge.sagepub.com/field5e. Without Andy Field`s explicit consent, this data set may not be distributed for commercial purposes, this data set may not be edited, and this data set may not be presented without acknowledging its source (i.e., the terms of a CC BY-NC-ND license).