Final answer:
A 95% probability that the interval contains the true difference in mean diameters is referred to as a confidence interval. The confidence interval provides a range of values that is likely to contain the true population parameter.
Step-by-step explanation:
A 95% probability that the interval contains the true difference in mean diameters from the two machines is referred to as a confidence interval. A confidence interval provides a range of values that is likely to contain the true population parameter, in this case, the difference in mean diameters. The 95% confidence interval is wider than a 90% confidence interval because it provides a higher level of certainty in containing the true value.