00:01
This question, we're told that a study reported that in a country, systolic blood pressure readings have a mean of 121.
00:07
So let's jot that down here.
00:11
And a standard deviation of 14.
00:13
It says a reading above 140 is considered to be high blood pressure.
00:19
So we're supposed to complete two parts of this question here.
00:22
The first part, part a, asks us to find the z score for a blood pressure reading of 140.
00:29
So x will be 140 and we're supposed to find the z score.
00:35
So to do that, we'll have to use this red equation i have on the screen.
00:39
So z is equal to x which is 140 minus the mean which the problem gave us as 121 divided by the standard deviation which the problem gave us to be 14.
00:52
If you calculate that you should get 1 .36.
00:56
So 1 .36 is our z score for 140.
01:01
Now in part b, it says that if sessolic blood pressure in this country is normally distributed, we are to find the proportion of the population in this country that suffers from high blood pressure...