Answer: (a) car exhaust; (b) chemicals and (d) people
Step-by-step explanation:
Indeed, it all starts from people. They are the ones who use the cars and make the pollution happen. It is also people who use chemicals to pan and find gold, for example, polluting rivers.
Answer:
1/2 or 0.5
Step-by-step explanation:
Because there is only 6 sides, the probability of it landing on a number greater than 3 is 1/2. On a 6 sided die 4,5 and 6 are all greater than 3. 1,2, and 3 are all less than 3. So 1/2 is the probability.
Answer:
a) 
b) 
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Let X the random variable that represent interest on this case, and for this case we know the distribution for X is given by:
And let
represent the sample mean, the distribution for the sample mean is given by:
(a) What are the mean and standard deviation of the sampling distribution?

On this case 
(b) What is the approximate probability that x will be within 0.4 of the population mean μ? (Round your answer to four decimal places.) P =
So for this case we want this probability:

And for this case we can use the z score given by this formula:

And using this concept we got this:

