00:01
For this question, there's given a normal distribution, and there are some given information here.
00:06
The population standard deviation, so this is the population standard deviation, which is denoted by sigma.
00:12
That was given as $5.
00:14
And the sample 49 americans, so that means the sample size was 49.
00:20
And the sample mean, the sample mean, which is denoted by x bar, this is equal to 20.
00:28
So we got these values.
00:29
Let's take a look at the first one.
00:32
So what is the point estimate of the population mean? so the point estimate of population mean, which is equal to the sample mean here.
00:47
And the sample mean was given as x bar, which is equal to 20.
00:51
And what about for b? so there's a confidence level here, which is given as 95%, which is 0 .95.
01:00
And when we look at the given values here, we know that the population standard deviation.
01:05
Since population standard deviation is known, so we have to use z test here.
01:17
Okay, so we have to get the interval, the confidence interval for mu.
01:22
So the confidence interval for me, which is equal to, this is x bar plus or minus, z alpha, over 2 times population standard division and divided by square of n.
01:33
Let's start with the alpha.
01:35
So the alpha is 1 minus confidence level.
01:39
And the alpha over 2 means this is 1 minus 0 .95 divided by 2, which is 0 .025.
01:46
Okay, then get the z alpha over 2 here, which is equal to z 0 .025...