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
#SPJ1
Answer: (8a^3x^3)/81
Step-by-step explanation: Simplifying the expression :)
Answer:
D) exponents are in decreasing order
Step-by-step explanation:
The answer is: gof = 1, 1, and 2
Answer:
Multiply row 2 by-1 and add it to row 3.
Step-by-step explanation:
The given augmented matrix is ![\left[\begin{array}{ccc}3&-21&15\\15&8&15\\-2&-1&3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%26-21%2615%5C%5C15%268%2615%5C%5C-2%26-1%263%5Cend%7Barray%7D%5Cright%5D)
The permissible row operations are:
1. Switching rows
2. Multiplying a row by a nonzero constant.
3. Adding/Subtracting two rows
Therefore the correct option is: Multiply row 2 by-1 and add it to row 3.
