Russell's study compared gpa of those students who volunteered for academic study skills training and those who did not elect to take the training. he found that those who had the training also had higher gpa. with which validity threat should russell be most concerned?

On february 3, smart company sold merchandise in the amount of $5,800 to truman company, with credit terms of 2/10, n/30. the cost of the items sold is $4,000. smart uses the perpetual inventory system and the gross method. truman pays the invoice on february 8, and takes the appropriate discount. the journal entry that smart makes on february 8 is:

Which one of the following statements is true? ddt does not prevent disease from passing from agricultural animals to humans. cost was a major factor in the united states government's decision to ban ddt. many african governments concluded that the potential long-term health effects of ddt were not as serious as the immediate problem of insect control. ddt cannot accumulate in the fat of animals. the ddt ban in the united states has made it very difficult to control agricultural insect pests.

For a firm that uses the weighted average method of process costing, which of the following must be true? (a) physical units can be greater than or less than equivalent units. (b) physical units must be equal to equivalent units. (c) equivalent units must be greater than or equal to physical units. (d) physical units must be greater than or equal to equivalent units.