The number of cars sold annually by used car salespeople is normally distributed with a standard deviation of 16. A random sample of 420 salespeople was taken and the mean number of cars sold annually was found to be 69. Find the 91% confidence interval estimate of the population mean.

Following are the calculation to the Confidence Interval:

Given:

To find:

Confidence Interval=?

Solution:

Here,

Therefore,

Now, confidence interval:  

Therefore, the final answer is "".

Learn more:

link

The 91% confidence interval estimate of the population mean is between 67.68 and 70.32 cars sold annually.

Step-by-step explanation:

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

So it is z with a pvalue of , so

Now, find the margin of error M as such

In which is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 69 - 1.32 = 67.68.

The upper end of the interval is the sample mean added to M. So it is 69 + 1.32 = 70.32

The 91% confidence interval estimate of the population mean is between 67.68 and 70.32 cars sold annually.

"image"

step-by-step explanation:

in most of these problems, the notation is that the point with a "prime" is the image of the point without. that is, b' is the image of b.

here, there is no dilation or reflection. there is simply translation (with no direction shown). which figure you call the "preimage" and which one you call the "image" is up to you. as a matter of convention, the naming is as described above.

2

step-by-step explanation: