A company wants to advertise their oven as extremely accurate - that when you set an oven for 350 degrees, the oven is very close to 350 degrees. The company randomly sampled thirty ovens to find that when set for 350 degrees, the oven had a reading with a 95% confidence level of [340, 360]. What sample size would you expect to need to have a 95% confidence level of [348, 352]?
a. 750
b. 150
c. 6
d. 35