cohort study {Ans: A study that observes and follows people moving forward in time from the time of their entry into the study.}Sampling with replacement {Ans: When a piece of the population can be selected more than once}Range {Ans: The difference between the minimum and maximum value in a given measurable set}Specification limits {Ans: The area, on either side of the centerline, or mean, of data plotted on a control chart that meets the customer's requirements for a product or service. This area may be greater than or less than the area defined by the control limits}Cumulative Average-Time Learning Model {Ans: A learning curve model in which the cumulative average time per unit declines by a constant percentage each time the cumulative quantity of units produced is doubled}Probability density function {Ans: Often used to represent probabilities of continuous data, a probability density function (pdf) gives the probability that a continuous random variable is equal to the area below it}