Use property of proportion:
miles time (hs)
90 2.25
x 1
x = 90 ÷ 2.25
x = 40 miles
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:
a squared+ 5a
Step-by-step explanation:
a(a+5)
multiply everything inside the bracket
a times a is a squared
a times 5 is 5a
i hope i helped
please give me a brainliest!!<3
Answer: 30
Step-by-step explanation: GOOD MORNING.
1 - 2/3 = 1/3
1+ (-1/3) = 2/3
