Answer:
B. 25%
Step-by-step explanation:
25 percent of 60 would be 15, then if you subtract 15 from 60, you end up with 45, meaning that 25 percent was subtracted.
A piece of wood 10 yards long
and
A piece of wood 5 feet long
He has two pieces of wood. How much does he have in all?
5+10 = 15
15 feet of wood
The z-value that corresponds to a two-tailed 95% confidence interval is z = +/- 1.96. Then the bounds of the confidence interval can be determined as:
Lower bound = mean - z*SD/sqrt(n) = 20 - 1.96*2/sqrt(100) = 20 - 0.12 = 19.88 hours
Upper bound = mean + z*SD/sqrt(n) = 20 + 1.96*2/sqrt(100) = 20 + 0.12 = 20.12 hours
So the first choice is the correct answer: 19.88-20.12 hours
