UC R Worksheet

#INSTRUCTIONS

#Type the codes for each question

#Include answers to ALL questions in the script as a comment (with a #).

#Questions with a * next to it will ALSO require you to input the answer in Canvas.

#Lastly, upload this R script AND input the corresponding answers to Canvas.

#If you are missing codes or answers in this script, points will be deducted.

#Download and call each package from library

install.packages(“openintro”)

install.packages(“dplyr”)

install.packages(“ggplot2”)

library(openintro)

library(dplyr)

library(ggplot2)

#Run data and view the name of variables

data(acs12)

names(acs12)

#The data is named “acs12”

View(acs12)

###CONFIDENCE INTERVALS

###EXAMPLE, solve the problems using this guideline###

#1. Construct a 95% CI for the average commute time for Americans (the variable we’re looking at is caled “time_to_work”)

#What is the interval for the average commute time? What does this mean?

#The average commute time is 24.4, 27.6 minutes. This means that we can be 95% confident that the average commute time is between these values.

t.test(acs12$time_to_work)

#*2. Construct a 95% CI for the average income and explain your results. The variable is called “income”

#*3. Construct a 95% CI for the average hours worked and explain your results. This variable is called “hrs_work”

#*4. Construct a 95% CI for the average age and explain your results. This variable is called “age”

### T-Tests HYPOTHESIS TESTS

###REMEMBER we REJECT the Ho if the p-value is LESS than alpha of 0.05

###EXAMPLE BELOW, solve the problems using this question

#5. Assume the average commute time of Americans is thought to be 26 min.

#Write the null hypothesis and the conclusion

#***This is a two-sided test, meaning we are not looking at greater or less than

#Ho: average commute = 26

#Ha: average commute NOT equal to 26

t.test(acs12$time_to_work, mu=26, alternative = “two.sided”)

#The p-value is 1 which is GREATER than alpha of 0.05. Therefore we FAIL TO REJECT the HO. The average commute is equal to 26

# *6. Assume that the average age is thought to be GREATER than 30.

#Write the null hypothesis and the conclusion

#*** This is a one-sided test, we are looking at GREATER than 30 as the alternative

#Ho:

#Ha:

# P-value and conclusion:

# *7. Assume that the average age is thought to be LESS than 50.

#Write the null hypothesis and the conclusion

#*** This is a one-sided test, we are looking at LESS than 50 as the alternative

#Ho:

#Ha:

# P-value and conclusion:

# *8. Assume that the average age is thought to be EQUAL TO 30.

#Write the null hypothesis and the conclusion

#*** This is a two-sided test, we are looking at “two.sided” as the alternative

#Ho:

#Ha:

# P-value and conclusion: