Answer:
≈28.62%
Step-by-step explanation:
Calculate number of standard deviations are 1,200 and 1,800 from the mean 2000.
z= (x-mean)/ standard deviation
z= (1,200-2000)/ 500 = -1.6
z= (1,800-2000)/ 500 = -.4
Find the percentage to the left of z that is -1.6 and -.4 standard deviations away from the mean by reading standard normal table for z-score.
z = -1.6 is .05840 so 5.84%
z= -.4 is .34458 so 34.458%
Find the percentage between 1,200mg and 1,800mg:
34.458 - 5.84 = 28.618%