Answer:
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:
On this case
Solution to the problem
We want this probability:
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:
The answer would be 6. Why? It's because of the 24%. You have to change the 24 into 0.24. If you left it alone, the process would be confusing. Changing it into a decimal is much easier. After you changed the percent into a decimal, multiply the 25. You should get 6 as an answer.
645 feet.
Explanation:
We know that are 3 feet in a yard, so let's set up a proportion to solve this
x215
3 feet n
-------- = -----------
1 yard 215 yards
x 215
We are solving for n. To get from 1 to 215, we multiply by 215. So to get from 3 to the answer, we must multiply by 215 as well. 3 x 215 = 645, therefore that is the answer.
Answer:
Exact Form:
x
=
64/21e
Decimal Form:
x
=
1.12115639
Step-by-step explanation: