00:01
Assuming a normal curve, so that means we could draw the bell -shaped curve, we want to find the lowest z score that a person could have while being in the following top percentages of a country in mathematics.
00:19
So we're looking at part a as being the top 10%.
00:24
So we're referencing this little section in here as being 10 % of the curve.
00:32
So if 10 % is above that value, that means there's 90 % below that value.
00:40
And we want to find the cutoff z score.
00:44
And the most efficient way to find that cutoff z score is using technology.
00:49
And i tend to use a texas instruments brand graphing calculator.
00:54
And the inverse norm function.
00:58
And when you use that inverse norm function on the texas instrument brand, you need to provide the area to the left of that location, followed by the mean and the standard deviation.
01:10
So for our scenario, the area to the left of this location, which separates the top 10 % from the bottom 90%, will be found by taking 0 .90, and with z, scores the mean is always zero and the standard deviation is one.
01:30
So i'm going to bring in my graphing calculator and once again it is a texas instruments brand calculator.
01:40
And to find inverse norm on the texas instruments calculator it's found using the second key and the distributions key which is above the vairs key and it happens to be number three in my submenu...