##Week 2 Homework ##By Catherine Cho
Question 1 Use the summary function to gain an overview of the data set. Then display the mean and median for at least two attributes.
#data set of bird strikes in US
birds<-read.csv("/Users/catherinecho/Documents/Data Sets/birds.csv")
summary(birds)## X opid operator atype
## Min. : 1 Length:19302 Length:19302 Length:19302
## 1st Qu.: 4826 Class :character Class :character Class :character
## Median : 9652 Mode :character Mode :character Mode :character
## Mean : 9652
## 3rd Qu.:14477
## Max. :19302
##
## remarks phase_of_flt ac_mass num_engs
## Length:19302 Length:19302 Min. :1.000 Min. :1.000
## Class :character Class :character 1st Qu.:3.000 1st Qu.:2.000
## Mode :character Mode :character Median :4.000 Median :2.000
## Mean :3.362 Mean :2.096
## 3rd Qu.:4.000 3rd Qu.:2.000
## Max. :5.000 Max. :4.000
## NA's :1284 NA's :1307
## date time_of_day state height
## Length:19302 Length:19302 Length:19302 Min. : 0.0
## Class :character Class :character Class :character 1st Qu.: 0.0
## Mode :character Mode :character Mode :character Median : 40.0
## Mean : 754.7
## 3rd Qu.: 500.0
## Max. :32500.0
## NA's :3193
## speed effect sky species
## Min. : 0.0 Length:19302 Length:19302 Length:19302
## 1st Qu.:110.0 Class :character Class :character Class :character
## Median :130.0 Mode :character Mode :character Mode :character
## Mean :136.1
## 3rd Qu.:150.0
## Max. :400.0
## NA's :7008
## birds_seen birds_struck
## Length:19302 Length:19302
## Class :character Class :character
## Mode :character Mode :character
##
##
##
## mean(birds$height, na.rm=TRUE)## [1] 754.6778median(birds$height, na.rm=TRUE)## [1] 40mean(birds$speed, na.rm=TRUE)## [1] 136.0993median(birds$speed, na.rm=TRUE)## [1] 130Question 2 Create a new data frame with a subset of the columns and rows. Make sure to rename it.
#subset data of bird strike time_of_day, state, height, and speed of Southwest Airlines
birds_1<-subset(birds,operator=="SOUTHWEST AIRLINES",select=c(10:13))Question 3 Create new column names for the new data frame.
colnames(birds_1)<-c("time","state_in_US","height_ft","speed_knots")Question 4 Use the summary function to create an overview of your new data frame. The print the mean and median for the same two attributes. Please compare.
summary(birds_1)## time state_in_US height_ft speed_knots
## Length:1096 Length:1096 Min. : 0 Min. : 30.0
## Class :character Class :character 1st Qu.: 0 1st Qu.:130.0
## Mode :character Mode :character Median : 100 Median :140.0
## Mean : 1271 Mean :156.2
## 3rd Qu.: 1500 3rd Qu.:180.0
## Max. :15000 Max. :320.0
## NA's :89 NA's :161mean(birds_1$height_ft, na.rm=TRUE)## [1] 1271.117median(birds_1$height, na.rm=TRUE)## [1] 100mean(birds_1$speed_knots, na.rm=TRUE)## [1] 156.2439median(birds_1$speed_knots, na.rm=TRUE)## [1] 140Question 5 For at least 3 values in a column please rename so that every value in that column is renamed. For example, suppose I have 20 values of the letter “e” in one column. Rename those values so that all 20 would show as “excellent”.
#renamed "night" values to "evening" in column "time"
birds_1$time[birds_1$time=="Night"]<-"Evening"Question 6 Display enough rows to see examples of all of steps 1-5 above.
#display first 20 rows
head(birds_1,n=20)## time state_in_US height_ft speed_knots
## 77 Day CA 1200 140
## 80 Evening TX 4000 250
## 132 Day TX 0 140
## 167 Day CA 150 130
## 175 Day TX 500 145
## 225 Day TX NA 180
## 231 Day IN 0 95
## 293 Evening CA 150 125
## 303 Day CA 10 135
## 320 Day CA 0 100
## 325 Evening TX 700 135
## 326 Day TX 0 120
## 368 Evening OK 1000 180
## 371 Day OK 50 135
## 442 Evening TX 3000 180
## 449 Evening <NA> NA NA
## 503 Day CA 100 138
## 510 Day TX 0 NA
## 530 Day AR 0 100
## 547 Day TX 100 145Question 7: Bonus BONUS – place the original .csv in a github file and have R read from the link. This will be a very useful skill as you progress in your data science education and career.
library(readr)
urlfile<-"https://raw.githubusercontent.com/catcho1632/Birds/main/birds.csv"
birddata<-read_csv(url(urlfile))## New names:
## * `` -> ...1## Rows: 19302 Columns: 18## ── Column specification ────────────────────────────────────────────────────────
## Delimiter: ","
## chr (13): opid, operator, atype, remarks, phase_of_flt, date, time_of_day, s...
## dbl (5): ...1, ac_mass, num_engs, height, speed##
## ℹ Use `spec()` to retrieve the full column specification for this data.
## ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.