In a study of the effectiveness of weightloss programs 47 su

In a study of the effectiveness of weight-loss programs, 47 subjects who were at least 20% overweight took part in a group support program for 10 weeks. Private weightings determined each subject’s weight at the beginning of the program’s end. The matched pairs t test was used to assess the significance of the average weight loss. The paper reporting the study said, “ the subject lost a significant amount f weight over time, t(46)=4.68, p < 0.01.” it is common to report the results of statistical test in this abbreviated style.

Why were the matched pairs statistics appropriate?

Explain to someone who knows no statistics but is interested in weight-loss programs what the practical conclusion is.

The paper follows the tradition of reporting significant only at fixed levels such as a=0.01. in fact, the results are more significant than p<0.01* suggest.What can you say about the p-value of the t test?

Solution

Since there are two samples data sets, with same subjects: One data set correponding to subjects weight at the beginning of the program and second data set correponding to subjects weight at the end of the program. And test is about the difference in weight (average weight loss), so matched pair t-test is used.

Matched pair becuase for same subject we are matching two values of weight.

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Result t(46)=4.68, p < 0.01 shows that p value is less than 0.01, so we reject the null hypothesis at 0.01 level of significance.

According to test, the result are significant. That is weight loss program is effective

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Since test statistics value is t=4.68 for df=46 so p-value of the test is 0.00026. P-value is less than 0.05 and also from 0.10. So we reject the null hypotheses at 0.05 and 0.10 level of significance. That is result is significant at 0.05 and 0.10 levels of significance.