## Comment: There is no power. (Score 4, Informative) 350

I am actually a statistician. And this 'study' looks pretty worthless.

The problem is the issue of a 'huge gap'. What gap is huge? Well, we can try and do a power calculation. How big does the gap between the black and white targets *need* to be, to have a good chance of showing up in this test?

This is simple enough to calculate. Plug in some numbers:

1. Sample size in each group - 50

2. Level of Significance - 0.05

3. Power - i.e. the desired probability of finding there to be a significant difference, *if a difference exists*. I've chosen a standard number of 0.8 - i.e. allow for a 20% chance of missing a true effect by accident.

Fixing the proportion of inappropriates for the white woman at 70%, we find.... 91.8%.

In other words, with this sample size, we actually only rule out a difference of 70% vs 91.8%, or in other words, an over 2/3rds drop in the proportion of people finding the picture appropriate.

To rephrase: **if the truth was that 2/3rds of the people who think a white woman is breastfeeding would *not* think a black person breastfeeding is appropriate - a situation that I think you'd agree is very racist - then we'd miss such an effect in an experiment like this over 1/5th the time**. Even assuming the experiment was conducted ideally, and no one was just randomly clicking to earn money.

This article is meaningless.