Step-by-step explanation:
given a normal distribution with the given parameters the probability (= the % of the area of the distribution curve) for a number to be between 203 and 1803 is
0.9987
so, 99.87% of all numbers are expected to be in that range.
for 350,000 numbers that means
350,000×0.9987 = 349,545 numbers are expected to be between 203 and 1803.
