00:01
Okay, so we've got a normal distribution, which will probably get a nice wide base, and the normal distribution has mean 145 and standard deviation 17 .5.
00:18
So they want us, firstly, for this question, they want us to draw the normal curve, which i've sort of sketched here, and they want us to label the mean and three standard deviations below and above it.
00:28
So the mean is always the central point of the normal distribution, so this is the mean at 145.
00:33
Then one standard deviation above and below is going to be about here, and this corresponds to 145 plus 17 .5, which is 162 .5, and 145 minus 17 .5, which is 127 .5.
00:56
For two standard deviations then, we're going to be somewhere here, and it's going to be 145 plus 2 times 17 .5, which is 180, and then over here it'll be 145 minus 2 times 17 .5, which is 110.
01:13
And finally, for three standard deviations, we're going to have 197 .5 for above and 92 .5 for below...