00:01
All right, in your question, you're asked to find the following probabilities from a standard normal distribution.
00:06
You are given the z scores.
00:09
So what we would do in a case like this, more than likely, we would be used z tables to find your answers.
00:15
I'm also going to provide sketches as necessary.
00:18
So the first one, what we're dealing with is a z score.
00:27
Zero would be in the middle.
00:28
1 .64 would be to the right, and we want the probability, which would be to the last.
00:33
Left of that value.
00:35
Now that's the way a z table is set up so we can look directly at a positive z table and it will give us the answer for that.
00:42
So that's my negative z table.
00:45
This is my positive.
00:45
I'm looking for 1 .6 and then 4.
00:50
So find that intersection.
00:52
It looks like 0 .945.
00:56
So write that answer down.
01:00
Move on to the next one.
01:02
Okay, so the next one the next one asks us to find the probability of z being greater than negative 1 .1.
01:16
So we have to do this one a little bit different because we want the area to the right of that value.
01:22
But our z table is going to give us this area to the left.
01:26
So let's go to the negative z table, negative 1 .1, and it would be 1 .10, so it's just this 0 .13.
01:36
And now to find our probability, we want to take 1 minus 0 .1357.
01:49
I'm going to pause that real quick and type that in the calculator.
01:54
Okay, so what i get for that answer would be 0 .8643.
02:02
Okay, moving on to the next one.
02:07
Let me draw another sketch of what we're looking for.
02:10
This one we want to find the area or the probability between 0 and 0 .8.
02:18
26.
02:20
So we're going to be looking for this area.
02:22
Now, our z table is going to give us the area the whole way to the left of this value.
02:28
But since they gave us one boundary at zero, we already know this is 50 % or 0 .5.
02:34
So i'm going to look up the 0 .26 in my z table here and we'll get that value...