Professor partridge has 9 seven-year-olds and 9 nine-year-olds study a set of pictures. he then asks the participants to verbally describe as many different pictures as possible. in this experiment, the independent variable is

Professor partridge has 9 seven-year-old and 9 nine-year-old study a set of pictures. He then asks the participants to verbally describe as many different pictures as possible. in this experiment, the independent variable is the AGE.

An experimental variable is referred to independent variable and variable quantity  is referred to dependent variable.
The difference between the dependent and independent variable is that the independent variable is not affected by any other variable,usually time.
Whereas,dependent variable totally depends upon the independent variable and changes according to the change in other variable.

The term that most effectively finishes this phrase is that of plaudits. In this passage, the narrator felt that the praise and motivation given by the coach was far more effective than the praise and applause that was being afforded to him or her by the crowd.