[srg0]

If learning durations were log-normally distributed, how would people be able to graduate from universities and finish studies, mostly in time? Or accomplish anything substantial in their limited time span?

I agree that distribution of most human tasks' duration is skewed (not necessarily distributed log-normally), but these tasks can still have a reasonable upper bound for completion. The success is not binary. Like in grading, we need to accept that some projects will get an A, and some will get only B or C, and it's still OK. Some may fail.

[baq]

A curriculum is designed. It's a product. It's optimised for teachers to deliver lessons in such a way that students can learn faster than log-normal.

Designing and implementing a curriculum is probably a log-normal effort.

[H8crilA]

Exactly. To see why notice that in a curriculum you are presented with both a problem and a solution. You are encouraged to find your own solutions to many problems, but regardless of whether you do you are also presented with the correct (optimal) solutions. This removes inaccuracies in your thinking, which would otherwise pile up multiplicatively, yielding a log-normal distribution of the time needed to master some topic.

[mrkeen]

> If learning durations were log-normally distributed, how would people be able to graduate from universities and finish studies, mostly in time?

By studying an exponentially smaller domain each time round:

* In primary school, study "The life-cycles of animals"

* In secondary school, study "mitosis and meiosis"

* As an undergrad, study "insect reproduction at a cellular level"

* As a postgrad, study "the effect of a particular molecule on the timing of a mosquito's development into sexual maturity"

[ahtihn]

> If learning durations were log-normally distributed, how would people be able to graduate from universities and finish studies, mostly in time?

If you took a hundred 5 year olds and set the objective to achieve the same PhD in the same field with unlimited time, guess how the time to achieve it would be distributed?

I'm sure some won't achieve it in their lifetime, so I disagree that there's a reasonable upper bound.