00:01
Hello, so let's look at some information given in a question.
00:07
Yeah, so we have the mean and you have the standard division.
00:11
So the mean was given us 21, standard division is one.
00:21
That's the information we got.
00:25
For the first part of the question, trying to figure out the 11th percentile for the incubation times.
00:34
So this is a normal distribution question, right? so you can say that p x minus a is 11 % or 0 .11.
00:51
Okay, now just by definition of percent out.
00:57
So you can go ahead and say the probability of x minus new standard deviation is less than a minus 21 over 1 is probably 0 .11 and that i can say this this right here is z right the one is less than a minus 211 i mean that's just a minus 211 equals 0 .11 so what is because we're trying to find a here right so what this means is we do to find a value that gives a probability of 0 .11 okay so we have to use the z table here so from the z table the value of z that gives the probability of 0 .1 that is a negative 1 .2 and that is going to be equal to a minus 2 so a is just going to be 21 minus 1 .2 today and that is going to be 19 .77 that is going to be 11 .77 now let's check the next question.
03:03
So for the next question, we've been giving a confidence interval to be 95%.
03:13
So we need to get the alpha value.
03:17
So the alpha value is 1 minus ci, a little bit 1 minus 95 % or 0 .05.
03:28
So once we have the alpha value, we need to get the alpha over 2 value.
03:33
That's 0 .025.
03:36
So we're going to use this to get a critical value of z...