Question 3 1 pts Which of the following are requirements to be checked when computing a confidence interval for a mean? (Mark ALL that apply) O A simple random sample was drawn from the population. O o is known. O x is normally distributed. Question 4 1 pts Bright Bulb light bulb company is planning a study to assess the average life expectancy of their light bulbs. They know the standard deviation is o = 400 hours. They want a 95% confidence interval with a margin of error of 50 hours. What sample size do they need? (Round up to the nearest whole number. Example: If you get 101.2 round to 102)