DATA 101 — Homework 2: Student Survey

Author

Dawit Merdassa

Set the working directory:

  1. Download “StudentSurvey.csv” to your computer.
  2. Set Working directory to the folder you saved your file in.
  3. Read the file using read.csv command.

Instructions:

Read the StudentSurvey into this document and answer the following questions.

# Read the StudentSurvey.csv in here
student_sur <- read.csv("StudentSurvey.csv")

Check the data structure:

# Check the head of the data set
head(student_sur)
       Year Sex Smoke   Award HigherSAT Exercise TV Height Weight Siblings
1    Senior   M    No Olympic      Math       10  1     71    180        4
2 Sophomore   F   Yes Academy      Math        4  7     66    120        2
3 FirstYear   M    No   Nobel      Math       14  5     72    208        2
4    Junior   M    No   Nobel      Math        3  1     63    110        1
5 Sophomore   F    No   Nobel    Verbal        3  3     65    150        1
6 Sophomore   F    No   Nobel    Verbal        5  4     65    114        2
  BirthOrder VerbalSAT MathSAT  SAT  GPA Pulse Piercings
1          4       540     670 1210 3.13    54         0
2          2       520     630 1150 2.50    66         3
3          1       550     560 1110 2.55   130         0
4          1       490     630 1120 3.10    78         0
5          1       720     450 1170 2.70    40         6
6          2       600     550 1150 3.20    80         4
# Check the dimensions
dim(student_sur)
[1] 362  17
# Check the structure (str) of the dataset.
# Name one numeric variable and one categorical variable below:
str(student_sur)
'data.frame':   362 obs. of  17 variables:
 $ Year      : chr  "Senior" "Sophomore" "FirstYear" "Junior" ...
 $ Sex       : chr  "M" "F" "M" "M" ...
 $ Smoke     : chr  "No" "Yes" "No" "No" ...
 $ Award     : chr  "Olympic" "Academy" "Nobel" "Nobel" ...
 $ HigherSAT : chr  "Math" "Math" "Math" "Math" ...
 $ Exercise  : num  10 4 14 3 3 5 10 13 3 12 ...
 $ TV        : int  1 7 5 1 3 4 10 8 6 1 ...
 $ Height    : int  71 66 72 63 65 65 66 74 61 60 ...
 $ Weight    : int  180 120 208 110 150 114 128 235 NA 115 ...
 $ Siblings  : int  4 2 2 1 1 2 1 1 2 7 ...
 $ BirthOrder: int  4 2 1 1 1 2 1 1 2 8 ...
 $ VerbalSAT : int  540 520 550 490 720 600 640 660 550 670 ...
 $ MathSAT   : int  670 630 560 630 450 550 680 710 550 700 ...
 $ SAT       : int  1210 1150 1110 1120 1170 1150 1320 1370 1100 1370 ...
 $ GPA       : num  3.13 2.5 2.55 3.1 2.7 3.2 2.77 3.3 2.8 3.7 ...
 $ Pulse     : int  54 66 130 78 40 80 94 77 60 94 ...
 $ Piercings : int  0 3 0 0 6 4 8 0 7 2 ...

Numeric variable: Weight______
Categorical variable: Sex______


# Create a table of students' sex and "HigherSAT"
table(student_sur$Sex,student_sur$HigherSAT)
   
        Math Verbal
  F   4   81     84
  M   3  124     66
# Display summary statistics for VerbalSAT
summary(student_sur$VerbalSAT)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
  390.0   550.0   600.0   594.2   640.0   800.0 
# Find the average GPA of students
mean(student_sur$GPA,na.rm = TRUE)
[1] 3.157942

# Create a new dataframe, call it "column_df". This new dataframe should contain students' weight and number of hours they exercise
column_df <- student_sur[c("Weight", "Exercise")]
# Access the fourth element in the first column from the StudentSurvey's dataset
student_sur[4,1]
[1] "Junior"
# How many students report an exercise time of more than 10 hours per week?
sum(student_sur$Exercise > 10, na.rm = TRUE)
[1] 123