Answer:
Step-by-step explanation:
Given that n =30, x bar = 375 and sigma = 81
Normal distribution is assumed and population std dev is known
Hence z critical values can be used.
For 95% Z critical=1.96
Margin of error = 
Confidence interval = 375±29
=(346,404)
B) 99% confidence
Margin of error = 2.59*Std error =38
Confidence interval = 375±38
=(337, 413)
C) For 90%
Margin of error = 20
Std error = 20/1.645 = 12.158
Sample size

Atleast 44 people should be sample size.
1) 2 bags cost $4 - from the graph
2) 1 bag would be just $2
Part A: r = d/t
Part B: 221760 feet per hour
Part C: 42 mph
Part D: Miles because we are measuring large distances