Answer:
Mean: 40.17 years.
Standard deviation: 10.97 years.
Step-by-step explanation:
The frequency distribution is in the attached image.
We can calculate the mean adding the multiplication of midpoints of each class and frequency, and dividing by the sample size.
The midpoints of a class is calculated as the average of the bounds of the class.
Then, the mean can be written as:
The standard deviation can be calculated as:
Right scalene triangle, because each side is a different length.
3(2x+2)+x+5=-10
6x+6+x+5=-10
7x+11=-10
7x=-21
x=-3
go that much "clockwise", you'll end up at the 2nd quadrant,
the reference angle, is its reflective angle on the 1st quadrant