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A normal curve for a made-up measurement is drawn on graph paper…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A normal curve for a made-up measurement is drawn on graph paper. It is symmetric about units. On the left it changes from bending up to bending down at units, and on the right it changes back at units. Find the mean and the standard deviation. Then find the range that holds the middle .
Need a reminder? The key ideaShow
A normal curve is fixed by and . About , and of values lie within one, two and three standard deviations of the mean (exactly , and ).
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The mean. The curve is symmetric about units, so units.
Step 2. The standard deviation. The bend changes at , so units.
Step 3. The middle . gives units to units.
Answer: units, units, and from units to units.
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