Question

"If you used the normal approximation to estimate how many of these measurements were in the range 400 to 406 micrograms, would your answer be too low, too high, or about right?

Answer 1

Explanation:

Prob(400<Xbar<406)=Prob(-13.338<t<2.77)=0.99

By normal approximation the no of measurements in the range of 400 to 406 is =n× 0.99=100 × 0.99=99

Which is slightly high compared to actual data.however we must consider that these approximation have an error component.so it is not accurate always.