Five measurements were taken in an oven where a product is c

Five measurements were taken in an oven where a product is cured at 350F. It is critical for the process that the curing occurs close to 350F. The measurements results are: X₁ 351, X₂ 352, X₃ 349, X₄ 355, X₅ 348 and the standard deviation from previous studies were found to be 1.2.

Determine the interval limits for this oven with 90% confidence (5)

Solution

The 90% CI is:

Mean plus minus z0.90*(sd/root over n)

=351 plus minus 1.645*(1.2/root over 5)

=351 plus minus 0.88

=(350.12,351.88)