Exercise 1 In a safari study in South Africa, zoologists were interested in examining the effect of malaria in buffaloes

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Exercise 1 In A Safari Study In South Africa Zoologists Were Interested In Examining The Effect Of Malaria In Buffaloes 1 (190.75 KiB) Viewed 123 times

Exercise 1 In a safari study in South Africa, zoologists were interested in examining the effect of malaria in buffaloes. To assess the ecological impact of malarial infection, the researchers tested 15 infected buffaloes for stamina. To quantify the stamina of each buffalo, as a proxy of it, they measured the distance in meters each animal could run in two minutes. For this sample of buffaloes, the sample mean was 26.87 m, while the standard deviation 6.81 m. 1. Construct and interpret a 90% confidence interval for the population mean distance run by buffaloes infected with malaria. 2. The researchers believe that the mean distance run by buffaloes infected with malaria is less than 30 m. Test this claim with a significance level of 0.05. 3. The zoologists want to plan a new study to estimate the population mean with a precision of 0.9m with 95% confidence. From previous studies, it is believed that the population standard deviation is approximately 7.71 m. What sample size should the researchers take? [Total: 25 marks]

Exercise 2 Ten institutionalized epileptic patients participated in a study of the anti-convulsant drug valproate. During an initial eight-week observation period, the patients were given valproate daily and the num- bers of major and minor epileptic seizures were counted for each patient. After this, during a second eight-week observation period, the patients were given an identical placebo pill daily and seizure counts were recorded. The numbers of minor seizures are given in the following table. Patient Valproate Placebo number period period 1 5 37 2 22 52 3 41 63 4 4 2 5 32 25 6 20 29 7 10 15 8 25 52 9 17 19 10 14 12 500 CON 1 1. What type of design is this? Explain. 2. Do these data contain evidence at the 5% significance level that valproate is efficacious in the treatment of epilepsy? 3. Construct a 95% confidence interval for the average difference in the count of minor seizures. [Total: 25 marks) a