Answer:
a) 95% percentage of people has an IQ score between 80 and 120.
b) 68% percentage of people has an IQ score between 90 and 110.
c) 2.5% percentage of people has an IQ score greater than 120.
Step-by-step explanation:
The empirical formula states that:
- The empirical rule is known as the three-sigma rule or 68-95-99.7 rule.
- It is a rule which states that for a normal distribution, almost all data falls within three standard deviations of the mean.
- 68% of data falls within the first standard deviation that is
- 95% of data falls within the second standard deviation that is
- 99.7% of data falls within the third standard deviation that is
a) percentage of people has an IQ score between 80 and 120
(80, 120) can be written as:

Thus, it is the interval within two standard deviation from the mean.
Thus, by empirical formula, 95% percentage of people has an IQ score between 80 and 120.
b) percentage of people has an IQ score between 90 and 110
(90, 110) can be written as:

Thus, it is the interval within one standard deviation from the mean.
Thus, by empirical formula, 68% percentage of people has an IQ score between 90 and 110.
c) P(score greater than 120)
= 1 - percentage of score less than 80 - percentage of score between 80 and 120

From empirical formula,
2.5% percentage of people has an IQ score greater than 120.
So this is going to be alot of writing to show my thinking but ill bold the answer.
1,1
1,2
1,3
1,4
1,5
2,1
2,2
2,3
2,4
2,5
3,1
3,2
3,3
3,4
3,5
4,1
4,2
4,3
4,4
4,5
5,1
5,2
5,3
5,4
5,5
next ill mark all the ones that equal 4 or 8 when added together, with an x
1,1
1,2
x1,3
1,4
1,5
2,1
x2,2
2,3
2,4
2,5
x3,1
3,2
3,3
3,4
x3,5
4,1
4,2
4,3
x4,4
4,5
5,1
5,2
x5,3
5,4
5,5
that is 6 (that equal 4 or 8) out of 25
so your ratio would be 6:19