Answer:
Coordinates switch, and the new y-coordinate changes sign
Explanation:
We have point A with the coordinates (-1,2), when we rotate it c90º it becomes (2,1).
What happened? The coordinates switched and the x-coordinate of A (-1) became the y-coordinate of A' (1) and it changed its sign.
Answer:
And using the normal standard table or excel we find the probability:
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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 avergae number of weeks an individual is unemployed 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:
We select a sample of n =50 people. And we want to find the following probability
And using the normal standard table or excel we find the probability:
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<span>one way to solve this kind of problems is by doing a little bit of reversal
75 % * X = 54
75/100 * X = 54
(we move 75/100 to the right, since it's a fraction the top and bottom number will be reversed)
X = 54 * 100/75
X = 5400 / 75
X = 72 Hope I helped! :) Cheers!</span>