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.
Yes, -0.5 is an integer because it is a negative number. Any number that is positive or negative is an integer.
1) we calculate the volume of the first carton:
volume=length x width x height
volume=3 ft * 2 ft * 2 ft=12 ft³
Therefore:
A machine can fill 12 ft³ in 3 seconds.
2) we calculate the volume of the second carton.
volume=length x width x heigth
volume=4 ft * 5 ft * 6 ft=120 ft³
3) we calculate the time that the machine needs for fill the second carton with packing material by the rule of three.
12 ft³---------------------3 seconds
120 ft³-------------------- x
x=(120 ft³ * 3 seconds) / 12 ft³=30 seconds.
answer: 30 seconds.
The slope of the line is -4/3