Rachel loves to bake cookies, but she has an old oven that has trouble maintaining a constant temperature. Assume the acceptable temperature range for making the cookies is 350 plus or minus 22 degrees. Six Sigma quality (3.4 defects per million units produced) is probably a bit much to ask of Rachels old oven.

a. What would the standard deviation in the temperature of her oven need to be if she settled for a Three Sigma level of quality?

b. If her oven exactly meets a Three Sigma quality level, what percentage of the time would her oven be operating at a temperature outside the acceptable range? Use Table 6-5.

please try answering b as I already have a.

TABLE 6-5 How Quality Relates To Sigma The Classical View of Quality "99.9\% Good" (4.6) - 20,000 lost articles of mail per hour. - Unsafe drinking water almost 15 minutes each day. - 5,000 incorrect surgical operations per week. - 2 short or long landings at most major airports daily. - 200,000 wrong drug prescriptions each year. - No electricity for almost 7 hours each month. The Six Sigma View of Quality "99.99966\% Good" (6) - Seven lost articles of mail per hour. - One minute of unsafe drinking water every seven months. - 1.7 incorrect surgical operations per week. - One shorts or long landing at major airports every five years. - 68 wrong drug prescriptions each year