49 of 50 Studying people over a long period of time is a feature of: O experimental research. survey research. observational research. O longitudinal research. 50 of 50 A researcher is examining motor...

Extracted text: 49 of 50 Studying people over a long period of time is a feature of: O experimental research. survey research. observational research. O longitudinal research. 50 of 50 A researcher is examining motor skill development by observing children at 18-months old, 24- months old, and 30-months old. If the researcher uses a longitudinal design and obtains 20 scores for each age, how many children participated in the entire study? O 20 40 60 Cannot determine without more information.