The following table shows the results of a study where participants received either a statin or a placebo and they were observed for the outcome of stroke.  Stroke No stroke  Statin1090100 Placebo4555100  55145200 Calculate the risk difference.Enter your answer in the text box below.

The following table shows the results of a study where participants received either a statin or a placebo and they were observed for the outcome of stroke.  Stroke No stroke  Statin1090100 Placebo4555100  55145200 Calculate the event rate of the treatment group.Enter your answer in the text box below.

Time left 0:07:23Question 8Not yet answeredMarked out of 1.00Flag questionTipsQuestion textA trial examining a new intervention and measuring the outcome of stroke had a final result of:RR 1.2, 95%CI 0.9 to 1.5.Select the best interpretation of this result.Question 8Answera.The intervention increased the average risk of stroke by 20% and the real result is likely to lie between a 10% decrease and a 50% increase. The result is not significant.b.The intervention increased the average risk of stroke by 20% and the real result is likely to lie between a 10% decrease and a 50% increase. The result is significant.c.The intervention decreased the average risk of stroke by 20% and the real result is likely to lie between a 10% increase and a 50% decrease. The result is not significant.d.The intervention decreased the average risk of stroke by 20% and the real result is likely to lie between a 10% increase and a 50% decrease. The result is significant.

What is the definition of the risk difference?Question 4Answera.The difference in proportion of subjects with the outcome of interest in each groupb.The number of patients you need to give an intervention to in order to prevent one additional negative outcomec.One minus the risk ratiod.The probability of an event in the treatment group divided by the probability of an event in the control group

Which of the following would increase the risk of stroke?W. Hypertension and smoking.X.  A metastatic tumour entering the circle of Willis.Y.  Atherosclerosis of the carotid arteries.Z.  Atrial fibrillation.Question 24Select one:a.if only W, X and Y are correctb.if only W and Y are correctc.if only X and Z are correctd.if only Z is correcte.if all are correc

A study reports a mortality rate of 6% in the experimental group and 10% in the control group. Which of the following statements is correct?Question 4Select one:a.None of options are correctb.The risk difference is 4%c.The RR is approximately 1.67d.The number needed to treat is 10e.The incidence of death is 6%