Please help i don't know what I'm doing
2 answers:
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Answer:
Step-by-step explanation:
We know that the length is four times the width, so:
We also know the area, which is 324 m². The formula for area:
Insert the known values:
Solve for w. Simplify by removing parentheses:
Divide 4 from both sides to isolate the variable:
Find the square root of both sides:
The width is 9 m.
We know the width. Now find the length by using the area formula and inserting known values:
Solve for l. Divide both sides by 9:
The length of the rectangle is 36. (You can check: 4 times 9 is 36)
Now find the perimeter:
Insert values:
The perimeter is 90 m.
Answer:
If we divide both sides by we got:
And we can use the normal distribution table or excel to find the probabilites 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 area of a population, and for this case we know the distribution for X is given by:
Where and
We select a a sample of n =4 and since the distribution for X is normal then we know that the distribution for the sample mean is given by:
And we want to find this probability:
If we divide both sides by we got:
And we can use the normal distribution table or excel to find the probabilites and we got: