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: no
Step-by-step explanation: to change a fraction back to a improper fraction
multiply the whole number by the denominator and then add it to the numerator but be careful with negative. You can check this process by changing the improper fraction back to proper. If i change -17/10 i get -1 7/10. the correct answer is -23/10.
Answer:
- Parallelogram has two pairs of parallel sides.
- Square has four right angles, two pairs of parallel sides, and all sides congruent.
- Trapezoid has only one pair of parallel sides.
Step-by-step explanation:
Answer:
169
Step-by-step explanation:
x−2=13
First find the value of x
x-2+2 = 13+2
x = 15
Now substitute into the expression
x^2 -4x+4
15^2 -4*15+4
225 - 60+4
165+4
169