An Explanation Or Answer?
2 answers:
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Answer:
1. y=5-2x
2. -y=5-2x
3.
Step-by-step explanation:
1. 2x+y=5
y=5-2x
2. 2x-y=5
-y=5-2x
3. x+2y=5
2y=5-x
Answer:
We can use the z score formula given by:
If we use this formula we got:
And using a calculator, excel or the normal standard table and we have that:
Step-by-step explanation:
We assume this previous info: It is known that the amounts of time required for room-service delivery at a certain Marriott Hotel are Normally distributed with the average delivery time of 20 minutes.
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 delivery times of a population, and for this case we know the distribution for X is given by:
Where and
Since the distribution for X is normal then the distribution for the sample mean is given by:
And we can use the z score formula given by:
If we use this formula we got:
And using a calculator, excel or the normal standard table and we have that: