Answer:
There is a 95% confidence that the sample has a mean between 158.92 pounds and 171.48 pounds
Step-by-step explanation:
Given that mean (μ) = 165.2 pounds, standard deviation (σ) = 12.4 pounds, sample size (n) = 15 crates. Confidence (C) = 95% = 0.95
α = 1 - C = 1 - 0.95 = 0.05
α/2 = 0.05/2 = 0.025
The z score of α/2 corresponds to the z score of 0.475 (0.5 - 0.025) which is 1.96. 
The margin of error (E) is given by:

The confidence interval = μ ± E = 165.2 ± 6.28 = (158.92, 171.48)
The confidence interval is between 158.92 pounds and 171.48 pounds. There is a 95% confidence that the sample has a mean between 158.92 pounds and 171.48 pounds
Answer:
5.625¢
Step-by-step explanation:
The amount of energy used by the chandelier is ...
5 × 0.075 kW × 1.5 h = 0.5625 kWh
At 10¢ per kWh, the cost will be ...
0.5625 kWh × 10¢/kWh = 5.625¢ . . . . cost of operation for 90 minutes
19) B
20) D
21) A
22) B
23) C
24) C
22 x 85 = (20+2)*85= 20*85+ 2*85 = 1700 + 170 = 1870