Answer: The margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.
Step-by-step explanation:
Since we have given that
Sample size = 400
Mean = $357.75
Standard deviation = $37.89
At 95% confidence level, z = 1.96
We first find the margin of error.
Margin of error is given by

95% confidence interval would be

Hence, the margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.
Answer:
B.
Step-by-step explanation:
Perpendicular lines always intercept at a right angle (90 degrees).
Answer:
7
Step-by-step explanation:
The answer is use the perpendicular bisectors to find the center of the circle.
Multiply first equaton by 2 and add to the other equation
6x+6y=12
<u>5x-6y=15 +</u>
11x+0y=27
11x=27
divide both sides by 11
x=27/11
sub back
3x+3y=6
divide both sides by 3
x+y=2
(27/11)+y=2
2 and 5/11+y=2
minus 2 and 5/11 both sides
y=-5/11
x=27/11
y=-5/11
(27/11,-5/11)