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:
k ≥ -18
Step-by-step explanation:

Answer:
answer for the question is 87
Answer:
b
Step-by-step explanation:
When you add the decimals it’s the same as regular adding. You line up the decimals and then add all the way across and when you get to the decimal carry it down