Sample size: planned number of observations
We ran pilots to test the functionality of our webpage and to estimate the parameters for a power calculation. Based on these pilots, we estimate the required sample size for a two-sample means test (power 0.8, alpha 0.05) to lie in the range of 150 to 500 subjects. We note that the power calculations based on the pilots are quite imprecise in terms of required sample sizes. This is due to the high share of workers stating a WTP of zero (up to 70% in some subgroups), leading to imprecise estimations of the standard deviation of the stated WTP.