Ok, MissWalker! Please try your best to understand this, it may get confusing.
I have solved this on a different website, and here is my solving in a picture. I hope I helped!!! :D
Answer:
And we can find this probability with the normal standard distirbution or excel and we got:
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".
Solution to the problem
Let X the random variable that represent the lenghts of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with the normal standard distirbution or excel and we got:
Answer:

Step-by-step explanation:

Answer:
A. 77
B. 3,773
Step-by-step explanation:
According to the problem, computation of given data are as follows,
Population in 2017 = 3,850
Decrease rate = 2% per year
(A) We can calculate number of population decrease from 2017 to 2018 by using following formula,
Number of population decrease = Population in 2017 × Decrease rate
= 3,850 × 2%
= 77
(B). Total population in 2018 = 3,850 - 77
= 3,773
Answer:
g
Step-by-step explanation: