On a number line, 7.7 would be located. Choose all answers that make a
2 answers:
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Answer:
And we can find this probability using the complement rule and the normal standard table or excel:
The firgure attached illustrate the problem
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 retirement savings 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 using the complement rule and the normal standard table or excel:
The firgure attached illustrate the problem
First let's get rid of the in the denominator of the fraction on the right side of the equation. This will help to get only
and a coefficient on one side of the equation:
Now, simply divide by 730 to find :