Final answer:
A nutritionist studying the time spent eating and drinking in a random sample would likely use a survey. This gathers structured responses about habits, which are then interpreted. This approach, unlike an observational study or an experiment, does not involve direct manipulation of variables by the researcher.
Step-by-step explanation:
A nutritionist who wants to determine the time spent eating and drinking in a random sample of 958 people would most likely conduct a survey. This method involves structured interviews where all respondents are asked the same set of questions, which could include how much time they spend on eating and drinking. The nutritionist would then tabulate and interpret the answers to derive conclusions about the eating and drinking habits of the sample population.
In the context of the study provided where soda consumption is investigated in relation to the development of diabetes, the type of observational study being conducted would be considered an observational study since the researcher is not manipulating the independent variable but is instead collecting data on naturally occurring phenomena.
To elaborate on an example given, a psychologist conducting an experiment to see if the size of tableware influences how much college students eat would define the population as all college students, the sample as the 100 college students participating, the experimental units as the individual students in the study, the explanatory variable as the size of the tableware, the treatment as the use of tableware that is 20 percent smaller than normal, and the response variable as the amount of food consumed by each group.