The question emphasizes the need for the most efficient discontinuous measurement procedure for tracking multiple students in a group setting for a behavior like ontask which is a state behavior meaning it occurs over an extended period Momentary Time Sampling MTS involves observing the behavior only at the very end of a predetermined interval This method is highly efficient for group observations because the observer only needs to check each students behavior at a specific discrete point in time allowing them to quickly cycle through multiple students within an observation period It provides a good estimate of the percentage of time the behavior occurs Partial Interval Recording PIR requires the observer to mark if the behavior occurred at any point during the interval This method is less efficient for multiple students as it demands more constant attention to each student within each interval to capture any occurrence Whole Interval Recording WIR requires the behavior to occur for the entire duration of the interval This is also demanding and less efficient for group observation as the observer must continuously monitor each student throughout the interval Event recording also known as frequency or count is a continuous measurement procedure not discontinuous It involves counting every instance of a behavior While accurate for discrete behaviors it would be extremely difficult and highly inefficient if not impossible to accurately track the frequency of ontask behavior for 10 students simultaneously as ontask is a continuous state rather than a discrete countable event Therefore among the discontinuous methods Momentary Time Sampling is the most practical and efficient choice for this scenario involving a group of learners