Question

During an investigation into an unsolved hit-and-run case, police are testing a paint sample to see if it matches a standard. The paint is analyzed for its content of iron oxide (Fe2O3), which gives paint its red color. Five measurements gave a mean of 43.35 (wt%) with a Standard Deviation of 0.33. A certain color reference provided by an automotive manufacturer is 44.2%. Does the sample match the reference at a 95% confidence level? If so, why?

Answer 1

Since the confidence interval does not include 44.2, so at 95% level of confidence we can conclude that color reference is significantly from automotive manufacturer's claim, i.e. 44.2%.