Answer:
(0.4958, 0.7422)
Step-by-step explanation:
Let p be the true proportion of water specimens that contain detectable levels of lead. The point estimate for p is
. The estimated standard deviation is given by
. Because we have a large sample, the 90% confidence interval for p is given by
where
is the value that satisfies that above this and under the standard normal density there is an area of 0.05. So, the confidence interval is
, i.e., (0.4958, 0.7422).
Answer:
The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Step-by-step explanation:
The area of a sphere is given by the following formula:

In which A is the area, measured in cm², and r is the radius, measured in cm.
Assume that the radius r of a sphere is expanding at a rate of 40 cm/min.
This means that 
Determine the rate of change in surface area when r = 20 cm.
This is
when
. So

Applying implicit differentiation.
We have two variables, A and r, so:



The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
For number 3 it would be |-10| and |10|.
Number 5a is supposed to <, because -1 is greater than -7 when you look at the line graph. The same goes for 5b. 5d is >, because 0 is always greater than -1 and it shows that on the line graph that you have there. 5e is =.
I don't see anything else wrong though. Just the ones I listed.
Hope that helps!
Answer:
175 students walk to school
Step-by-step explanation:
300+250+325=875
20% of 875 is 175