Your friend Sam has been asked to prepare appetizers for the university reception. She has an unlimited amount of ingredients and six hours in which to prepare them. Sam can make 500 mini-sandwiches or 400 servings of melon slices topped with smoked salmon and a dab of sauce per hour.

a. Draw Sam’s production possibilities frontier.
b. Now suppose that the university decides to postpone the reception until after the big game, and Sam has an extra 4 hours to prepare.

c. Now, in addition to the extra time to prepare, suppose Sam’s friend Chris helps by preparing the melon slices. Sam can now make 300 mini-sandwiches or 300 melon appetizers per hour. Redraw Sam’s production possibilities frontier to show the impact of increased productivity in making melon appetizers.

Reliability and validity reliability and validity are two important considerations that must be made with any type of data collection. reliability refers to the ability to consistently produce a given result. in the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways. unfortunately, being consistent in measurement does not necessarily mean that you have measured something correctly. to illustrate this concept, consider a kitchen scale that would be used to measure the weight of cereal that you eat in the morning. if the scale is not properly calibrated, it may consistently under- or overestimate the amount of cereal that’s being measured. while the scale is highly reliable in producing consistent results (e.g., the same amount of cereal poured onto the scale produces the same reading each time), those results are incorrect. this is where validity comes into play. validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. while any valid measure is by necessity reliable, the reverse is not necessarily true. researchers strive to use instruments that are both highly reliable and valid.