TABLE $6-5$ How Quality Relates To Sigma

The Classical View of Quality $"99\mathrm{.}9\%$ Good" $(4\mathrm{.}6)$

$20,000$ 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 $"99\mathrm{.}99966\%$ Good" $(6)$

Seven lost articles of mail per hour.

One minute of unsafe drinking water every seven months.

$1\mathrm{.}7$ incorrect surgical operations per week.

One shorts or long landing at major airports every five years.

$68$ wrong drug prescriptions each year.

One hour without electricity every $34$ years.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 $20$ degrees. Six Sigma quality $(3\mathrm{.}4$ defects per million units produced$)$ is probably a bit much to ask of Rachel$$s old oven.

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

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 $6-5.$