Question One:
The .csv file labeled gpigs gives the survival time in days of 72 guinea pigs after they were infected with tubercle bacilli in a medical experiment.
In this case, we can count the guinea pigs as a random sample, and as such use the standard deviation of the sample as the standard deviation of the population.
QUESTION: What do we expect the average survival time of the population of guinea pigs to be after they have been injected?
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Question Two:
There is some evidence that increasing the amount of calcium in the diet can lower blood pressure. In a medical experiment, one group of males were given a calcium supplement while the control group received a placebo. Before the experiment takes place, we measure the blood pressure of all the men that were slated for each group.
Because these are the selected groups, we should be VERY wary for removing any points.
To find the standard deviation, use ALL patients in a group as the sample. You may then use the standard deviation of that as the standard deviation of the population.
QUESTION: Are there differences between the group slated for calcium and that slated for placebo? As part of your comparison, make some type of graph that shows both groups on the same graph. Make sure to also compare CI for each group.
Calciumgroup<-c(107, 110, 123, 129, 112, 111, 107, 112, 136, 102)
Placebogroup<-c(123, 109, 112, 102, 98, 114, 119, 112, 110, 117, 130)
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Question 3:
One way of determining success in a company is to compare the amount of profit per employee. a 1.8, for example, means that the company had a profit of 1.8 thousand dollars for each employee they employ.
The standard deviation of the population of businesses is about 3.8.
The standard deviation for banks is about 10.2.
The .csv file PPE.csv contains a random sampling from both banks and the retail.
QUESTION: Compare and contrast the Bank PPE to that of the Retailers. Make sure to include some type of graph that shows both sets of data as well as a strong stastistical analysis.
(This question was adapted from and uses data from the book "Understandable Statistics: Concepts and Methods" by Charles and Corrinne Brase, Tenth Edition)