Answer:
By the Chebyshev's Theorem, the minimum percentage of recent graduates who have salaries $22,800 and $30,000 is 89%.
Step-by-step explanation:
Chebyshev's theorem states that:
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 26,400
Standard deviation = 1200
Between $22,800 and $30,000
22800 = 26400 - 3*1200
So 22800 is 3 standard deviations below the mean
30000 = 26400 + 3*1200
So 30000 is 3 standard deviations above the mean.
By the Chebyshev's Theorem, the minimum percentage of recent graduates who have salaries $22,800 and $30,000 is 89%.