Question 1142560
The 99%CI would be z(0.995)*sigma/sqrt(n), and that has to be < 1.7
so 2.576*10.1/sqrt(n) <1.7
square both sides
676.916/n < 2.89
so 676.916/2.89<n
or n > 676.916/2.89
n>234.22 or 235