The answer is A. I plugged it into a TI-83 calculator. If you need to know how I did that I will be happy to help
Answer:
8
Step-by-step explanation:
0 has no value what so ever when adding and subtracting.
As described in z-distribution the answers are given below:
a) The 95% confidence interval estimate for the population mean spending by a customer on visiting salon per month is given as follows: (747, 853).
b) The sampling error at 95% confidence level is of: $35.78.
What is a z-distribution ?
The normal distribution with a mean of 0 and a standard deviation of 1 is referred to as the standard normal distribution (also known as the Z distribution) (the green curves in the plots to the right). It is frequently referred to as the bell curve since the probability density graph resembles a bell.
solution:
The bounds of the confidence interval are given as follows:
In which:
is the sample mean.
z is the critical value.
n is the sample size. is the standard deviation for the population.
The parameters for this problem are given as follows:
Hence the lower bound of the interval is of:
800 - 200 x 1.96/square root of 55 = 747.
The upper bound of the interval is of:
800 + 200 x 1.96/square root of 55 = 853.
The sampling error for a sample size of 120 is calculated as follows:
200 x 1.96/square root of 120 = $35.78.
To learn more about the z-distribution from the given link
brainly.com/question/4079902
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Volume of water will it take to fill in the well is 4710 cubic feet
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Solution:</u></h3>
Given that a cylindrical well has a radius of 10 feet
Height of cylindrical well = 15 feet
To find: volume of water will it take to fill in the well
Since, the well is in the form of cylinder, This means that we need to find the volume of cylindrical well
<em><u>The volume of cylinder is given as:</u></em>

Where "r" is the radius and "h" is the height of cylinder
Substituting the given values we get,


Hence, the amount of water that can be stored in the well is 4710 cubic feet