MGSC 291 Exam 1 University of South Carolina exam questions with answers

MGSC 291 Exam 1 University of South
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Carolina exam questions with answers |\ |\ |\ |\




putting in a dataset - CORRECT ANSWERS ✔✔data<-
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c(81,85,93,93,99,76,75,84,78,84,81,82,89,81,96,82,74,70,84,86,8
0,70,131,75,88,102,115,89,82,79,106)


length(data) - CORRECT ANSWERS ✔✔tells you how may entries
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are in your vector
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sort(data) - CORRECT ANSWERS ✔✔puts data smallest to largest
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summary(data) - CORRECT ANSWERS ✔✔returns the five number |\ |\ |\ |\ |\ |\ |\ |\


summary and the sample mean |\ |\ |\ |\




mean(data)
sd(data)
sum(data) - CORRECT ANSWERS ✔✔sample mean
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sample standard deviation
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adds all the elements of the vector
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seq(1,100,1) |\




seq(2,100,2) - CORRECT ANSWERS ✔✔tells r to create the
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sequence of numbers from 1 to 100 by 1 (1,2,3...)
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,1:100 does the same thing
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(2,4,6...100)


data<-read.table(file.choose(),header=TRUE)
read.cvs - CORRECT ANSWERS ✔✔calls this dataset into r and
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you can name it whatever you want
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getwd() - CORRECT ANSWERS ✔✔creates the current working
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directory and calls in your data too
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dim(data) - CORRECT ANSWERS ✔✔checks dimensions of data
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data - CORRECT ANSWERS ✔✔type the name of the data to see it
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data[1:5] - CORRECT ANSWERS ✔✔calls in the first five rows of
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the dataset if you are working with a large dataset
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head(data) - CORRECT ANSWERS ✔✔shows the first few rows
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data[,1:2] - CORRECT ANSWERS ✔✔all rows for columns 1 and 2
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data[1:5,1:2] - CORRECT ANSWERS ✔✔first five rows and first two
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columns
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str(data) - CORRECT ANSWERS ✔✔structure of the object
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, View(data) - CORRECT ANSWERS ✔✔(capital V) puts your data in
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a viewable popup window
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data$shoes - CORRECT ANSWERS ✔✔calls in the column called
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shoes


attach(data) - CORRECT ANSWERS ✔✔attaches data so you can
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work with it and don't have to keep calling it in
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(if you attach several datasets that have the same column names
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r will be confused so you have to detach before attaching again)
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data<-subset(data,Type=="WT") - CORRECT ANSWERS ✔✔you |\ |\ |\ |\ |\


can pick out certain rows/columns and you can enter more ==
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and "" in order to be more specific
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hist(data) - CORRECT ANSWERS ✔✔give you a histogram
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hist(data,breaks=c(60,70,80,90)) - CORRECT ANSWERS |\ |\ |\ |\


✔✔creates a sequence and breaks them |\ |\ |\ |\ |\




xlab="percents of ..." - CORRECT ANSWERS ✔✔x axis name |\ |\ |\ |\ |\ |\ |\ |\




ylab="Frequency" - CORRECT ANSWERS ✔✔y axis name |\ |\ |\ |\ |\ |\