Question

All one question just formatted weird

A health educator wants to evaluate the effect of a safety film on the frequency with which children wear their bicycle helmets. Eight (8) children are selected for the experiment. First, a baseline number of times the children wear their helmets is measured over the period of a month. Next, the same children are shown a safety film and again the researcher measures the number of times the children wear their helmets in the month following the film. The health educator wanted to know if watching the film changed the frequency of wearing bicycle helmets. The following data are collected: Child: 1 2 3 After Film 28 31 Before Film 2028 4 19 20 5 30 30 6 25 21 7 28 23 8 32 27 25 22 Question 18 1 pts What is the appropriate statistical test for this study? HTML Editore B I VA - A - I EIT 1XXE B. D O NVX 12pt - Paragraph -

Answer 1

In this example we have two sets of paired samples, since the measurements were made on the same childem before and after the film. To see if there was an impoovement, deterioration or it the means of time have remained substantially the soome we need to make a students t- test for paired samples. Hypothesis & Ho: Up = 0 Hi! Up & 0 vs U The X - X = up and difference between the paired values d [x, - x2) is distributed with mean variance (6.2 + 62 - 236162) The test statistic is on = d. Salon t = 3.4941 - R output. tain = 1.8946 to tant

Hence, we reject to at 51 level of significance It confirms that there is a significant difference between the wearing bicycle helmets before and after the film.

Console - > X=C(28,31, 19, 30, 25, 28, 32,27) > y=C(20,28,20,30,21,23,25,22) > t.test(x,y.paired = TRUE) Paired t-test data: x and y t - 3.4941, df = 7, p-value = 0.01007 alternative hypothesis: true difference in means is not equal to o 95 per cent confidence interval: 1.2526 6.4974 sample estimates: mean of the differences 3.875 > qt (0.95,7) [1] 1.894 579