Question

Rachel loves to bake cookies, but she has an old oven that has trouble maintaining a constant temperature. If the acceptable temperature range for making the cookies is 350 plus or minus 18 degrees, what is the allowable standard deviation in the temperature of her oven in order to achieve a Six Sigma level of quality? (Round your answer to 3 decimal places.)

Answer 1

σ = 3

Step-by-step explanation:

Given:

For 6 sigma level of quality z = 6

Upper Specific Limit = 350 + 18 = 368°

Lower Specific Limit = 350 - 18 = 332°

Now,

z = (USL - LSL)/6σ

where, σ is the standard deviation

the standard z value is 2 for 6 sigma level of quality

thus we have

2 = (368° - 332°)/(6 × σ)

or

σ = 3 (answer)