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Yes and no, people have relatively convergent views on usability. Statistically, you can think of proposition A "user from set U affirms that object O has prope
by ivalm 7y ago
Yes and no, people have relatively convergent views on usability. Statistically, you can think of proposition A "user from set U affirms that object O has property Q". You then sample opinions for U on whether this proposition is true. Each sampling is a Bernoulli trial parametrized by
p = Prob(A = True)
The standard error of the mean is then
sqrt(p*(1-p)/N)
where N is how many users you sampled. Suppose people are convergent in their opinion (either p=0.99 or 0.01) then even with N=5 the uncertainty in mean is less than 5%!
To make a concrete example, you only need to ask very few users if a particular object is white to be fairly confident whether the majority of people would consider a particular object to be white.
- rosser 7y agoThat is to say, if all five of the users with whom you've tested your application say it's confusing, or it sucks somehow, it is diminishingly likely for that population to be the outlier [0], and if only you had tested with a few tens or dozens — let alone thousands — more, you'd see the true pattern... Yes, statistically, it's possible for outliers to bunch like that. It's also, statistically, far less likely. [0] Assuming, for sake of argument, a nominally representative test group.