1. A Researcher Studied The Effect Of Television V

1. A researcher studied the effect of television violence on concentration of a particular blood chemical. In this study, 40 participants were measured over a period of an hour prior to watching a violent show and then immediately after. In the results section, the researcher writes: ʺThere was a significant decline in blood concentration from a mean of 13.41 (SD=2.48) to 12.38 (SD=2.69), t(39)=3.38, p<.01 (one tailed).ʺ Explain this result (including the underlying logic of the computations) to a person who understands hypothesis testing involving a single sample and a known population, but knows nothing about t tests.Here we were comparing the population mean of blood concentration before and after watching a violent show. We measured the blood concentration of same participants before watching a violent show and after watching a violent show. This type of design is known as paired design because the same measurement was taken on the same observation before and after some activity. We can use paired sample t test if the data is obtained before and after the treatment. In this case, a paired sample t test was used to test whether there is any significant decrease in mean blood concentration before and after watching