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.
Answer:
34
Step-by-step explanation:
17(2)=34
Answer:
Total cost = Cost per month × 12 months per year × Number of years
= $21 × 12 × 8
= $2,016
Step-by-step explanation:
Answer:
-5
Step-by-step explanation:
1: simplify both sides of the equation. (combine like terms)
2: subtract 3x from both sides
3: subtract 16 from both sides
4: divide both sides by 3
i hope that helped!