In a within-subjects study that extends over a relatively long time, it is possible that there will be systematic changes in the participants’ skills or knowledge during the time of the study. When these changes influence the participants’ scores, causing scores at the end of the study to be different from scores at the beginning, the effect is called .A) a history effect.
B) instrumentation.
C) maturation.
D) regression toward the mean.

A) a history effect.          

Explanation:

History effect: In psychological research, the term "history effect" is described as different events that generally occurs in the specific environment which is responsible for changing the pre-existing conditions of a particular study, therefore affecting or hindering its outcome. However, these history events can occur either between post-test &pre-test or before starting a specific experiment.

In the question above, the given statement signifies a history effect.

well its not not rising unemployment and falling inflation.

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