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).
Simple,
2.) If a circle is divided into 9 parts and your are trying to find three of those parts, first find what is 1 of those parts...
In a circle there is 360°
360/9=40
That is 1 part.
For three parts it would be 40*3=120
Your answer is 120°
3.) Do the same thing here.
A circle is 360°
360/10=36
Now, for four of those parts...
36*4=144
The answer is 144°.
Pretty fast consider 115ft wasn't enough to avoid an accident..