Y axis values not displaying correctly

tidyverse
1

I am trying to plot a bar graph to show a students travel time which will be displayed on the y axis and x axis should display the students grades. The highest grade a student can obtain is 20. When I plot the graph in a box_plot the value display correctly. However, when displayed as a bar graph the grade values are 2000, 4000 and so on. On the box plot, the values displayed are 5,10,15 and so on. I used this code to change the values into numeric which worked
data$G3 <- as.numeric(as.character(data$G3))

Below is the code to display the bar graph.

ggplot(data, aes(x=traveltime, y=G3, fill = traveltime)) + geom_bar(stat = "identity") +
labs(x="Travel time", y="Student grade") +
ggtitle("Plot to show how a students travel time can affect their final grade") +
scale_fill_manual("traveltime", values = c("1" = "purple", "2" = "turquoise", "3" = "blue", "4" = "yellow")) +
theme_classic()

Below is the output of the graph.

Rplot07

May I please have help on how to change the y axis to the appropriate values.

2

Please post your data. You can do that by posting the output of dput.

dput(data)

If that is too large, you can choose the number of rows with the head() function.

dput(head(data,20))

Place lines with three back ticks just before and after the pasted output in your reply, like this
```
Pasted output from dput goes here
```

3

this is the output data

\\

structure(list(index = c("index", "1", "2", "3", "4", "5", "6",
"7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17",
"18", "19"), school = c("school", "GP", "GP", "GP", "GP", "GP",
"GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP",
"GP", "GP", "GP"), sex = c("sex", "F", "F", "F", "F", "F", "M",
"M", "F", "M", "M", "F", "F", "M", "M", "M", "F", "F", "F", "M"
), age = c("age", "18", "17", "15", "15", "16", "16", "16", "17",
"15", "15", "15", "15", "15", "15", "15", "16", "16", "16", "17"
), address = c("address", "U", "U", "U", "U", "U", "U", "U",
"U", "U", "U", "U", "U", "U", "U", "U", "U", "U", "U", "U"),
famsize = c("famsize", "GT3", "GT3", "LE3", "GT3", "GT3",
"LE3", "LE3", "GT3", "LE3", "GT3", "GT3", "GT3", "LE3", "GT3",
"GT3", "GT3", "GT3", "GT3", "GT3"), Pstatus = c("Pstatus",
"A", "T", "T", "T", "T", "T", "T", "A", "A", "T", "T", "T",
"T", "T", "A", "T", "T", "T", "T"), Medu = c("Medu", "4",
"1", "1", "4", "3", "4", "2", "4", "3", "3", "4", "2", "4",
"4", "2", "4", "4", "3", "3"), Fedu = c("Fedu", "4", "1",
"1", "2", "3", "3", "2", "4", "2", "4", "4", "1", "4", "3",
"2", "4", "4", "3", "2"), Mjob = c("Mjob", "at_home", "at_home",
"at_home", "health", "other", "services", "other", "other",
"services", "other", "teacher", "services", "health", "teacher",
"other", "health", "services", "other", "services"), Fjob = c("Fjob",
"teacher", "other", "other", "services", "other", "other",
"other", "teacher", "other", "other", "health", "other",
"services", "other", "other", "other", "services", "other",
"services"), reason = c("reason", "course", "course", "other",
"home", "home", "reputation", "home", "home", "home", "home",
"reputation", "reputation", "course", "course", "home", "home",
"reputation", "reputation", "course"), guardian = c("guardian",
"mother", "father", "mother", "mother", "father", "mother",
"mother", "mother", "mother", "mother", "mother", "father",
"father", "mother", "other", "mother", "mother", "mother",
"mother"), traveltime = c("traveltime", "2", "1", "1", "1",
"1", "1", "1", "2", "1", "1", "1", "3", "1", "2", "1", "1",
"1", "3", "1"), studytime = c("studytime", "2", "2", "2",
"3", "2", "2", "2", "2", "2", "2", "2", "3", "1", "2", "3",
"1", "3", "2", "1"), failures = c("failures", "0", "0", "3",
"0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0",
"0", "0", "0", "3"), schoolsup = c("schoolsup", "yes", "no",
"yes", "no", "no", "no", "no", "yes", "no", "no", "no", "no",
"no", "no", "no", "no", "no", "yes", "no"), famsup = c("famsup",
"no", "yes", "no", "yes", "yes", "yes", "no", "yes", "yes",
"yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
"yes"), paid = c("paid", "no", "no", "yes", "yes", "yes",
"yes", "no", "no", "yes", "yes", "yes", "no", "yes", "yes",
"no", "no", "yes", "no", "no"), activities = c("activities",
"no", "no", "no", "yes", "no", "yes", "no", "no", "no", "yes",
"no", "yes", "yes", "no", "no", "no", "yes", "yes", "yes"
), nursery = c("nursery", "yes", "no", "yes", "yes", "yes",
"yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
"yes", "yes", "yes", "yes", "yes"), higher = c("higher",
"yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
"yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
"yes"), internet = c("internet", "no", "yes", "yes", "yes",
"no", "yes", "yes", "no", "yes", "yes", "yes", "yes", "yes",
"yes", "yes", "yes", "yes", "no", "yes"), romantic = c("romantic",
"no", "no", "no", "yes", "no", "no", "no", "no", "no", "no",
"no", "no", "no", "no", "yes", "no", "no", "no", "no"), famrel = c("famrel",
"4", "5", "4", "3", "4", "5", "4", "4", "4", "5", "3", "5",
"4", "5", "4", "4", "3", "5", "5"), freetime = c("freetime",
"3", "3", "3", "2", "3", "4", "4", "1", "2", "5", "3", "2",
"3", "4", "5", "4", "2", "3", "5"), goout = c("goout", "4",
"3", "2", "2", "2", "2", "4", "4", "2", "1", "3", "2", "3",
"3", "2", "4", "3", "2", "5"), Dalc = c("Dalc", "1", "1",
"2", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1",
"1", "1", "1", "1", "2"), Walc = c("Walc", "1", "1", "3",
"1", "2", "2", "1", "1", "1", "1", "2", "1", "3", "2", "1",
"2", "2", "1", "4"), health = c("health", "3", "3", "3",
"5", "5", "5", "3", "1", "1", "5", "2", "4", "5", "3", "3",
"2", "2", "4", "5"), absences = c("absences", "6", "4", "10",
"2", "4", "10", "0", "6", "0", "0", "0", "4", "2", "2", "0",
"4", "6", "4", "16"), G1 = c("G1", "5", "5", "7", "15", "6",
"15", "12", "6", "16", "14", "10", "10", "14", "10", "14",
"14", "13", "8", "6"), G2 = structure(c(NA, NA, NA, 3L, 4L,
3L, 4L, NA, NA, NA, 4L, NA, NA, NA, NA, NA, NA, NA, 3L, 2L
), .Label = c("0", "5", "10", "15", "20"), class = "factor"),
G3 = c(NA, NA, NA, 10, 15, 10, 15, NA, NA, NA, 15, NA, NA,
NA, NA, NA, NA, NA, 10, 5)), row.names = c(NA, 20L), class = "data.frame")

\\

4

Making a bar chart of the data set in its current form does not make sense. Each value of traveltime appears multiple times with different values of G3. What ggplot is doing is stacking all of the G3 values, effectively giving you the sum of G3 for each travel time. I illustrate this in the code below by setting the color aesthetic to white, so each bar has a white outline. You can see in the filtered data I named DF2 that there are six occurrences of traveltime = 1 and one of travel time = 3 and the plot shows each of those stacked on top of each other.
What do you want the bar plot to show?
As an aside, the first row of the data is what should be the headers. I deleted that row. You probably have to modify how you read in the data.

library(dplyr)

library(ggplot2)
DF <- structure(list(index = c("index", "1", "2", "3", "4", "5", "6",
                               "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17",
                               "18", "19"), 
                     school = c("school", "GP", "GP", "GP", "GP", "GP",
                                "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP", "GP",
                                "GP", "GP", "GP"), 
                     sex = c("sex", "F", "F", "F", "F", "F", "M",
                             "M", "F", "M", "M", "F", "F", "M", "M", "M", "F", "F", "F", "M"
                     ), 
                     age = c("age", "18", "17", "15", "15", "16", "16", "16", "17",
                             "15", "15", "15", "15", "15", "15", "15", "16", "16", "16", "17"
                     ), 
                     address = c("address", "U", "U", "U", "U", "U", "U", "U",
                                 "U", "U", "U", "U", "U", "U", "U", "U", "U", "U", "U", "U"),
                     famsize = c("famsize", "GT3", "GT3", "LE3", "GT3", "GT3",
                                 "LE3", "LE3", "GT3", "LE3", "GT3", "GT3", "GT3", "LE3", "GT3",
                                 "GT3", "GT3", "GT3", "GT3", "GT3"), 
                     Pstatus = c("Pstatus",
                                 "A", "T", "T", "T", "T", "T", "T", "A", "A", "T", "T", "T",
                                 "T", "T", "A", "T", "T", "T", "T"), 
                     Medu = c("Medu", "4",
                              "1", "1", "4", "3", "4", "2", "4", "3", "3", "4", "2", "4",
                              "4", "2", "4", "4", "3", "3"), 
                     Fedu = c("Fedu", "4", "1",
                              "1", "2", "3", "3", "2", "4", "2", "4", "4", "1", "4", "3",
                              "2", "4", "4", "3", "2"), 
                     Mjob = c("Mjob", "at_home", "at_home",
                              "at_home", "health", "other", "services", "other", "other",
                              "services", "other", "teacher", "services", "health", "teacher",
                              "other", "health", "services", "other", "services"), 
                     Fjob = c("Fjob",
                              "teacher", "other", "other", "services", "other", "other",
                              "other", "teacher", "other", "other", "health", "other",
                              "services", "other", "other", "other", "services", "other",
                              "services"), 
                     reason = c("reason", "course", "course", "other",
                                "home", "home", "reputation", "home", "home", "home", "home",
                                "reputation", "reputation", "course", "course", "home", "home",
                                "reputation", "reputation", "course"), 
                     guardian = c("guardian",
                                  "mother", "father", "mother", "mother", "father", "mother",
                                  "mother", "mother", "mother", "mother", "mother", "father",
                                  "father", "mother", "other", "mother", "mother", "mother",
                                  "mother"), 
                     traveltime = c("traveltime", "2", "1", "1", "1",
                                    "1", "1", "1", "2", "1", "1", "1", "3", "1", "2", "1", "1",
                                    "1", "3", "1"), 
                     studytime = c("studytime", "2", "2", "2",
                                   "3", "2", "2", "2", "2", "2", "2", "2", "3", "1", "2", "3",
                                   "1", "3", "2", "1"), 
                     failures = c("failures", "0", "0", "3",
                                  "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0",
                                  "0", "0", "0", "3"), 
                     schoolsup = c("schoolsup", "yes", "no",
                                   "yes", "no", "no", "no", "no", "yes", "no", "no", "no", "no",
                                   "no", "no", "no", "no", "no", "yes", "no"), 
                     famsup = c("famsup",
                                "no", "yes", "no", "yes", "yes", "yes", "no", "yes", "yes",
                                "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
                                "yes"), 
                     paid = c("paid", "no", "no", "yes", "yes", "yes",
                              "yes", "no", "no", "yes", "yes", "yes", "no", "yes", "yes",
                              "no", "no", "yes", "no", "no"), 
                     activities = c("activities",
                                    "no", "no", "no", "yes", "no", "yes", "no", "no", "no", "yes",
                                    "no", "yes", "yes", "no", "no", "no", "yes", "yes", "yes"
                     ), 
                     nursery = c("nursery", "yes", "no", "yes", "yes", "yes",
                                 "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
                                 "yes", "yes", "yes", "yes", "yes"), 
                     higher = c("higher",
                                "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
                                "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes", "yes",
                                "yes"), 
                     internet = c("internet", "no", "yes", "yes", "yes",
                                  "no", "yes", "yes", "no", "yes", "yes", "yes", "yes", "yes",
                                  "yes", "yes", "yes", "yes", "no", "yes"), 
                     romantic = c("romantic",
                                  "no", "no", "no", "yes", "no", "no", "no", "no", "no", "no",
                                  "no", "no", "no", "no", "yes", "no", "no", "no", "no"), 
                     famrel = c("famrel",
                                "4", "5", "4", "3", "4", "5", "4", "4", "4", "5", "3", "5",
                                "4", "5", "4", "4", "3", "5", "5"), 
                     freetime = c("freetime",
                                  "3", "3", "3", "2", "3", "4", "4", "1", "2", "5", "3", "2",
                                  "3", "4", "5", "4", "2", "3", "5"), 
                     goout = c("goout", "4",
                               "3", "2", "2", "2", "2", "4", "4", "2", "1", "3", "2", "3",
                               "3", "2", "4", "3", "2", "5"), 
                     Dalc = c("Dalc", "1", "1",
                              "2", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1",
                              "1", "1", "1", "1", "2"), 
                     Walc = c("Walc", "1", "1", "3",
                              "1", "2", "2", "1", "1", "1", "1", "2", "1", "3", "2", "1",
                              "2", "2", "1", "4"), 
                     health = c("health", "3", "3", "3",
                                "5", "5", "5", "3", "1", "1", "5", "2", "4", "5", "3", "3",
                                "2", "2", "4", "5"), 
                     absences = c("absences", "6", "4", "10",
                                  "2", "4", "10", "0", "6", "0", "0", "0", "4", "2", "2", "0",
                                  "4", "6", "4", "16"), 
                     G1 = c("G1", "5", "5", "7", "15", "6",
                            "15", "12", "6", "16", "14", "10", "10", "14", "10", "14",
                            "14", "13", "8", "6"), 
                     G2 = structure(c(NA, NA, NA, 3L, 4L,
                                      3L, 4L, NA, NA, NA, 4L, NA, NA, NA, NA, NA, NA, NA, 3L, 2L
                     ), .Label = c("0", "5", "10", "15", "20"), class = "factor"),
                     G3 = c(NA, NA, NA, 10, 15, 10, 15, NA, NA, NA, 15, NA, NA,
                            NA, NA, NA, NA, NA, 10, 5)), row.names = c(NA, 20L), class = "data.frame")
DF <- DF %>% slice(-1) #remove the first row

#inspect the data
DF2 <- DF %>% select(traveltime, G3) #select just the two columns of interest for display
DF2
#>    traveltime G3
#> 1           2 NA
#> 2           1 NA
#> 3           1 10
#> 4           1 15
#> 5           1 10
#> 6           1 15
#> 7           1 NA
#> 8           2 NA
#> 9           1 NA
#> 10          1 15
#> 11          1 NA
#> 12          3 NA
#> 13          1 NA
#> 14          2 NA
#> 15          1 NA
#> 16          1 NA
#> 17          1 NA
#> 18          3 10
#> 19          1  5
DF2 %>% filter(!is.na(G3)) #remove all the NA rows
#>   traveltime G3
#> 1          1 10
#> 2          1 15
#> 3          1 10
#> 4          1 15
#> 5          1 15
#> 6          3 10
#> 7          1  5

#plot the full data set
ggplot(DF, aes(x=traveltime, y=G3, fill = traveltime)) + geom_bar(stat = "identity", color = "white") +
  labs(x="Travel time", y="Student grade") +
  ggtitle("Plot to show how a students travel time can affect their final grade") +
  scale_fill_manual("traveltime", values = c("1" = "purple", "2" = "turquoise", "3" = "blue", "4" = "yellow")) +
  theme_classic()
#> Warning: Removed 12 rows containing missing values (position_stack).

Created on 2022-04-29 by the reprex package (v0.2.1)

5

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