Answer:

So then the probability that an individual present and IQ higher than 3 deviation from the mean is 0.00135
And if we find the number of individuals that can be considered as genius we got: 0.00135*1500=2.025
And we can say that the answer is a.2
Step-by-step explanation:
1) 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".
2) Solution to the problem
Let X the random variable that represent the IQ scores of a population, and for this case we know the distribution for X is given by:
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:

And we can find the following probablity:

So then the probability that an individual present and IQ higher than 3 deviation from the mean is 0.00135
And if we find the number of individuals that can be considered as genius we got: 0.00135*1500=2.025
And we can say that the answer is a/2.0
Answer: 14/15
This is because to get to 14/15 you must divide by 6 but when getting to 42/45 you must divide 2. Therefore 14/15 is your answer because the problem went to the most reduced fraction.
D, 12y is also 12 • y and when there is an answer to a multiplication problem, it’s a product. and that minus 2 is subtracting.
1) Put all the numbers in numerical order :
15, 23, 24, 25, 25, 25, 27
The median is the middle of the numbers : 25
Mode is the value that occurs more often : 25
2) Put all the numbers in numerical order :
2, 3, 3, 3, 3, 4, 4, 5
The middle of the numbers is 3 and 3
so, 3 + 3 = 6
6 : 2 = 3
Median = 3
Mode = 3
3) Put all the numbers in numerical order :
5, 7, 8, 9, 9, 10, 10, 10, 12
Median = 9
Mode = 10
4) Put all the numbers in numerical order :
0, 1, 1, 2, 2, 3, 3, 3, 4, 4
Median
2 + 3 = 5 : 2 = 2,5
Mode = 3
5) Put all the numbers in numerical order :
12, 13, 15, 18, 25
Median = 15
Mode = 0 (None)
6) Put all the numbers in numerical order :
1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 5
Median = 3
Mode = 3 and 4
7) Put all the numbers in numerical order :
6, 8, 9, 10, 10, 12
Median
9 + 10 = 19 : 2 = 8
Mode = 10
8) Put all the numbers in numerical order :
28, 30, 30, 30, 30, 31, 31, 31, 31, 31, 31, 31
Median
31 + 31 = 62 : 2 = 31
Mode = 31