Answer:
3) (98.08, 124.16)
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 111.12
Standard deviation = 13.04
Calculate an interval that is symmetric around the mean such that it contains approximately 68% of fines.
68% of the fines are within 1 standard deviation of the mean speed. So
From 111.12 - 13.04 = 98.08 to 111.12 + 13.04 = 124.16
The interval notation in the smallest value before the highest value.
So the correct answer is:
3) (98.08, 124.16)
Answer is 36.
20 * 80/100 = 16
20+16=36
