The mean score is 60 out of 100 and the standard deviation (in other words, the variation in the scores) is 15 marks (see our statistical guides, Measures of Central Tendency and Standard Deviation, for more information about the mean and standard deviation).
What Are the Six Different Types of Swimming Strokes? Swimming provides all-around, low-impact body conditioning as well as exciting competition. Competitive swim meets allow only four strokes -- butterfly, backstroke, breaststroke and the crawl. Two other strokes -- elementary backstroke and sidestroke -- contribute to swimming longer distances, as different sets of muscles are used. The fastest stroke for most swimmers is the front crawl.
Backstroke is pretty much the same as front stroke, apart from your body is the other way round. Instead of lying on your front, you lie on your back, kicking your legs the same way as you do in freestyle, and you raise your arms, which starts by your side, comes back over your head, and into the water.he is the most basic stroke of them all, as well as the fastest. It involves your knees touching, kicking your legs, and raising your arms alternately out of the water, over your head, and back in the water again, in a windmill motion.