I've been taking tests lately because I am interesting in getting a computer job. The tests cause me to feel anxious, make lots of mistakes, and pause in terror. After working out the mean from five separate results, I got a result of 65 wpm, which is ok, but I'm sure in reality its closer to 75.
When I'm taking the tests, I feel the need to be perfect and it caused me to panic. As a result I make a lot more mistakes in typing tests than I do when I'm casually typing something for myself.
When I'm under pressure, I'm not sure whether to look at the screen, or occassionally peek at my fingers, and whenever I made an error I would freak out, pause for a few moments then decide whether to fix it or continue writing, which must have brought my average down a lot.
Out of five tests, my lowest score was 52 words per minute, and my highest score was 79 words per minute.