Answer:
$76.80
Step-by-step explanation:
Domingo earns 715$ in the week that is his gross income
Intercept form is: y = a(x - p)(x - q)
It is given that: p = 14, q = -6, x = 14, y = 4
4 = a(14 - 12)(14 - (-6))
4 = a(2)(20)
4 = 40a
Answer: y = 
(x - 14)(x + 6)
The 68-95-99.7 rule tells us 68% of the probability is between -1 standard deviation and +1 standard deviation from the mean. So we expect 75% corresponds to slightly more than 1 standard deviation.
Usually the unit normal tables don't report the area between -σ and σ but instead a cumulative probability, the area between -∞ and σ. 75% corresponds to 37.5% in each half so a cumulative probability of 50%+37.5%=87.5%. We look that up in the normal table and get σ=1.15.
So we expect 75% of normally distributed data to fall within μ-1.15σ and μ+1.15σ
That's 288.6 - 1.15(21.2) to 288.6 + 1.15(21.2)
Answer: 264.22 to 312.98
