Homework 7

1.

str(iris)

150 obs. of  5 variables

2.

iris1 <-  filter(iris, Species %in% c("virginica", "versicolor") & Sepal.Length > 6 & Sepal.Width > 2.5)

56 obs. of  5 variables

3.

iris2 <- select(iris1, Species, Sepal.Length, Sepal.Width)

56 obs. of  3 variables

4.

iris3 <- arrange(iris2, by=desc(Sepal.Length))
head(iris3, 6)

    Species Sepal.Length Sepal.Width
1 virginica          7.9         3.8
2 virginica          7.7         3.8
3 virginica          7.7         2.6
4 virginica          7.7         2.8
5 virginica          7.7         3.0
6 virginica          7.6         3.0

5.

iris4 <- mutate(iris3, Sepal.Area=Sepal.Length*Sepal.Width)

56 obs. of  4 variables

6.

iris5 <- summarize(iris4, meanLength = mean(Sepal.Length), meanWidth = mean(Sepal.Width), TotalN = n())

  meanLength meanWidth TotalN
1   6.698214  3.041071     56

7.

iris_species <- group_by(iris4, Species)

iris6 <- summarize(iris_species, meanLength = mean(Sepal.Length), meanWidth = mean(Sepal.Width), TotalN = n())

print(iris6)

  Species    meanLength meanWidth TotalN
  <fct>           <dbl>     <dbl>  <int>
1 versicolor       6.48      2.99     17
2 virginica        6.79      3.06     39

8.

iris7 <- iris %>%
  filter(Species %in% c("virginica", 
                              "versicolor") & 
           Sepal.Length > 6 & Sepal.Width > 2.5) %>%
  select(Species, Sepal.Length, Sepal.Width) %>%
  arrange(by=desc(Sepal.Length)) %>%
  mutate(Sepal.Area=Sepal.Length*Sepal.Width)%>%
  group_by(Species)%>%
  summarize(meanLength = mean(Sepal.Length), meanWidth = mean(Sepal.Width), TotalN = n())

  Species    meanLength meanWidth TotalN
  <fct>           <dbl>     <dbl>  <int>
1 versicolor       6.48      2.99     17
2 virginica        6.79      3.06     39

9.

wideIRIS <- iris %>% 
  pivot_longer(
    cols=Sepal.Length:Petal.Width,
    names_to = "Measure",
    values_to = "Value")

wideIRIS

  Species Measure      Value
   <fct>   <chr>        <dbl>
 1 setosa  Sepal.Length   5.1
 2 setosa  Sepal.Width    3.5
 3 setosa  Petal.Length   1.4
 4 setosa  Petal.Width    0.2
 5 setosa  Sepal.Length   4.9
 6 setosa  Sepal.Width    3  
 7 setosa  Petal.Length   1.4
 8 setosa  Petal.Width    0.2
 9 setosa  Sepal.Length   4.7
10 setosa  Sepal.Width    3.2