What is the difference between internal validity and external validity? a. a statistical analysis is said to have internal validity if the statistical inferences about causal effects can only be verified by a few researchers. the analysis is said to have external validity if conclusions can be verified by many researchers. b. a statistical analysis is said to have external validity if the statistical inferences about causal effects are valid for the population being studied. the analysis is said to have internal validity if conclusions can be generalized to other populations and settings. c. a statistical analysis is said to have internal validity if the statistical inferences about causal effects are valid for the population being studied. the analysis is said to have external validity if conclusions can be generalized to other populations and settings. d. internal validity and external validity are equivalent.

Self-interest achieve society’s economic goals because producers know which goods consumers want the most. as consumers and producers exercise their freedom to act in their own self-interest, markets will produce the desired goods at the lowest possible cost. consumers and producers both operate based on society’s economic goals. consumers know which goods can be produced at the lowest cost. there is a wide variety of desired goods and services in a market system because producers determine what to produce. consumers change their minds frequently. there is always a need to produce something new and improved. individual wants are diverse. what is produced is ultimately determined by consumers, because if the goods offered are not what consumers want, consumers will not buy them. producers, because they are driven by profits. producers, because they determine what to produce. consumers, because they participate in marketing surveys.

Which of the following statements about revision is most accurate? (a) you must compose first drafts quickly (sprint writing) and return later for editing. (b) careful writers always revise as they write. (c) revision is required for only long and complex business documents. (d) some business writers prefer to compose first drafts quickly and revise later; others prefer to revise as they go.

Levine inc., which produces a single product, has prepared the following standard cost sheet for one unit of the product. direct materials (9 pounds at $1.80 per pound) $16.20 direct labor (6 hours at $14.00 per hour) $84.00 during the month of april, the company manufactures 270 units and incurs the following actual costs. direct materials purchased and used (2,500 pounds) $5,000 direct labor (1,660 hours) $22,908 compute the total, price, and quantity variances for materials and labor.