Answer:
The 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February is between $292.48 and $331.32
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 21 - 1 = 20
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 20 degrees of freedom(y-axis) and a confidence level of
. So we have T = 1.7247
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 311.9 - 19.42 = $292.48
The upper end of the interval is the sample mean added to M. So it is 311.9 + 19.42 = $331.32
The 90% confidence interval for the true mean natural gas bill for homes in the 19808 zip code area in February is between $292.48 and $331.32
Answer:
Step-by-step explanation:
The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try! A variable doesn't have to be "x", it could be "y", "w" or any letter, name or symbol.
Answer:
6000 dollars duhhhhhhhhhhhh
Answer:
x=0
Step-by-step explanation:
120521x=0
x=0/120521=0
Answer:
f(x) = 3 cos (2Pi / period value ; x )+ 2
or see answer using 2 as the period see answer in bold below.
Step-by-step explanation:
cosine function amplitude of 3 is A = 3
The period is used to find B
You need to show period value as the denominator and work out from there with 2PI as a function numerator to show as 2pi / period can be a data angle
C is the adding value.
Acos (Bx) + C
A = 3
Bx = 2 pi / period
C = + 2
However f 2 is also the period found
then we just plug in 2 to above formula
f(x) = 3 cos (2Pi / 2 ; x )+ 2
f(x) = 3cos (x pi) + 2