How to be more productive in study?please give tips​

Here is a quote from an npr news article: “on average, working-age adults were eating about 78 fewer calories per day in 2010, compared with five years earlier. the new report is based on data from the national health and nutrition examination survey, which collects details on eating habits and other health-related information from a nationally representative sample of about 10,000 people in the u.s.” which of the following is true about the numerical value 78? a. it is an anecdote. b. it is a parameter. c. it is a simulation. d. it is a statistic.

How can firms use marginal analysis to determine the price of a product? a) profit maximization can occur when the marginal cost exceeds the marginal revenue. b) the total cost of production can determine the individual unit price of a product. c) marginal analysis can be used to determine at what price profit maximization occurs. d) firms can calculate the marginal cost of a product and set the price lower than the cost.

Physical needs include: a. the need for sleep b. the need to feel safe c. the need to feel secure d. all of the above