First you find the median which is 4. The mean is calculated by the sum of the distribution divided by the amount of numbers in the distribution (20). The mean comes out to be 4.35. Subtract 4.35 from 4 and your answer is .35.
Step-by-step explanation:
= (1 + 5z)(-4)
= (1 + 5z) × (-4)
= 1.(-4) + 5z. (-4)
= -4 - 20z
It's 77.472 , but since you probably need too round it will be 77.5