00:01
Here on this problem, we have been given a frequency table, and we've been told that x is the randomly selected shuttle mission between april 1981 and july of 2000.
00:12
Part a asks us to define what are the possible values of the random variable x.
00:17
Well, since x is the crew size, then all the possible values are just the numbers of the crew size.
00:22
And so this means that x is an element of the sample space to...
00:32
Three, four, five, six, seven, and eight.
00:37
And so x can take on any of those given values.
00:43
Now b tells us to use random variable notation to represent the event that the shuttle mission obtained as a crew size of seven.
00:52
Now, random variable notation is in set like this.
00:56
And this would be when x is equal to seven.
01:00
And so this would be the event x equals seven.
01:03
That means you have crew size of seven.
01:09
Now c tells us to find that.
01:11
The probability that x is equal of four.
01:15
Now the probability that x is equal to four is equal to a numerator of two.
01:24
The reason the numerator is two is because there's two times that was the frequency.
01:29
And then for your denominator, do you need to know the total of number of events that happen? and so you add up everything in the frequency row.
01:37
Everything in the frequency row, and there are 96 total events.
01:41
So your probability is 2 over 96.
01:43
And they did want this as a percentage.
01:48
And so we take this and multiply it by 100.
01:56
This gives us 2 .08%.
02:00
So the probability that x is equal to 4 is 2 .08%.
02:09
Now details us to obtain the probability distribution of x.
02:16
Now for the probability distribution of x, let's make a table.
02:27
We said that all the values are 2 through 8...