Lasers can provide highly accurate measurements of small movements. To determine the accuracy of such a laser, it was used to take 100 measurements of a known quantity. The sample mean error was 25 μm with a standard deviation of 60μm. The laser is properly calibrated if the mean error is μ = 0. A test is made of H₀ :μ = 0 versus H₁ :μ ≠ 0.

a. Find the P-value.

b. Do you believe it is plausible that the laser is properly calibrated, or are you convinced that it is out of calibration? Explain your reasoning.