13. Correct. The answer is true


The test can be formulated as follows

H0: μ=0.060

Ha: μ ≠ 0.060, so a two-tailed test is required.

Under the H0, T=(`X- μ)(n-1)0.5/s=(0.063-0.060)*90.5/0.003=3.


For a two-tailed test at 5% level of significance, the decision rule is to reject H0 if T lies outside the interval (-t0.995 to +t0.995 ), which for (10-1) degrees of freedom is the interval -3.25 to 2.26. Reject H0 otherwise. Since T=3, we reject H0 at 5% level. The machine is therefore in the proper working conditions.