Hand washing has external health benefits, helping prevent the spread of communicable diseases. If a program were somehow devised so that people received a small reward every time they washed their hands, we would expect the frequency of hand washing to:. A) remain constant
B) increase
C) decrease and the number of people who are sick to:.
A) remain constant
B) increase
C) decrease

Hand washing has external health benefits, helping prevent the spread of communicable diseases. If a program were somehow devised so that people received a small reward every time they washed their hands, we would expect the frequency of hand washing to increase.

Explanation: People who are given something (A reward of some sort) are proven to do something more, (in this case washing their hands more), or better then they would do without a source of motivation.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.