library(dplyr)

Question 1

data(cars)
median_speed <- median(cars$speed)
print(median_speed)
[1] 15

Question 2

OnTimePerformance <- read.csv("On_Time_Performance.csv")
str(OnTimePerformance)
'data.frame':   570131 obs. of  110 variables:
 $ Year                : int  2018 2018 2018 2018 2018 2018 2018 2018 2018 2018 ...
 $ Quarter             : int  1 1 1 1 1 1 1 1 1 1 ...
 $ Month               : int  1 1 1 1 1 1 1 1 1 1 ...
 $ DayofMonth          : int  16 17 18 19 20 21 22 23 24 25 ...
 $ DayOfWeek           : int  2 3 4 5 6 7 1 2 3 4 ...
 $ FlightDate          : chr  "2018-01-16" "2018-01-17" "2018-01-18" "2018-01-19" ...
 $ UniqueCarrier       : chr  "AA" "AA" "AA" "AA" ...
 $ AirlineID           : int  19805 19805 19805 19805 19805 19805 19805 19805 19805 19805 ...
 $ Carrier             : chr  "AA" "AA" "AA" "AA" ...
 $ TailNum             : chr  "N128AN" "N128AN" "N121AN" "N129AA" ...
 $ FlightNum           : int  228 228 228 228 228 228 228 228 228 228 ...
 $ OriginAirportID     : int  12892 12892 12892 12892 12892 12892 12892 12892 12892 12892 ...
 $ OriginAirportSeqID  : int  1289206 1289206 1289206 1289206 1289206 1289206 1289206 1289206 1289206 1289206 ...
 $ OriginCityMarketID  : int  32575 32575 32575 32575 32575 32575 32575 32575 32575 32575 ...
 $ Origin              : chr  "LAX" "LAX" "LAX" "LAX" ...
 $ OriginCityName      : chr  "Los Angeles, CA" "Los Angeles, CA" "Los Angeles, CA" "Los Angeles, CA" ...
 $ OriginState         : chr  "CA" "CA" "CA" "CA" ...
 $ OriginStateFips     : int  6 6 6 6 6 6 6 6 6 6 ...
 $ OriginStateName     : chr  "California" "California" "California" "California" ...
 $ OriginWac           : int  91 91 91 91 91 91 91 91 91 91 ...
 $ DestAirportID       : int  12173 12173 12173 12173 12173 12173 12173 12173 12173 12173 ...
 $ DestAirportSeqID    : int  1217303 1217303 1217303 1217303 1217303 1217303 1217303 1217303 1217303 1217303 ...
 $ DestCityMarketID    : int  32134 32134 32134 32134 32134 32134 32134 32134 32134 32134 ...
 $ Dest                : chr  "HNL" "HNL" "HNL" "HNL" ...
 $ DestCityName        : chr  "Honolulu, HI" "Honolulu, HI" "Honolulu, HI" "Honolulu, HI" ...
 $ DestState           : chr  "HI" "HI" "HI" "HI" ...
 $ DestStateFips       : int  15 15 15 15 15 15 15 15 15 15 ...
 $ DestStateName       : chr  "Hawaii" "Hawaii" "Hawaii" "Hawaii" ...
 $ DestWac             : int  2 2 2 2 2 2 2 2 2 2 ...
 $ CRSDepTime          : int  2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 ...
 $ DepTime             : int  2010 2003 2008 2010 2001 2003 2003 2011 2122 2007 ...
 $ DepDelay            : num  -1 -8 -3 -1 -10 -8 -8 0 71 -4 ...
 $ DepDelayMinutes     : num  0 0 0 0 0 0 0 0 71 0 ...
 $ DepDel15            : num  0 0 0 0 0 0 0 0 1 0 ...
 $ DepartureDelayGroups: int  -1 -1 -1 -1 -1 -1 -1 0 4 -1 ...
 $ DepTimeBlk          : chr  "2000-2059" "2000-2059" "2000-2059" "2000-2059" ...
 $ TaxiOut             : num  24 18 14 17 17 17 24 23 26 18 ...
 $ WheelsOff           : int  2034 2021 2022 2027 2018 2020 2027 2034 2148 2025 ...
 $ WheelsOn            : int  2358 2348 6 2352 2352 1 14 2352 125 2357 ...
 $ TaxiIn              : num  7 5 6 3 5 4 3 14 3 2 ...
 $ CRSArrTime          : int  29 29 29 29 29 29 29 29 29 29 ...
 $ ArrTime             : int  5 2353 12 2355 2357 5 17 6 128 2359 ...
 $ ArrDelay            : num  -24 -36 -17 -34 -32 -24 -12 -23 59 -30 ...
 $ ArrDelayMinutes     : num  0 0 0 0 0 0 0 0 59 0 ...
 $ ArrDel15            : num  0 0 0 0 0 0 0 0 1 0 ...
 $ ArrivalDelayGroups  : int  -2 -2 -2 -2 -2 -2 -1 -2 3 -2 ...
 $ ArrTimeBlk          : chr  "0001-0559" "0001-0559" "0001-0559" "0001-0559" ...
 $ Cancelled           : num  0 0 0 0 0 0 0 0 0 0 ...
 $ CancellationCode    : chr  "" "" "" "" ...
 $ Diverted            : num  0 0 0 0 0 0 0 0 0 0 ...
 $ CRSElapsedTime      : num  378 378 378 378 378 378 378 378 378 378 ...
 $ ActualElapsedTime   : num  355 350 364 345 356 362 374 355 366 352 ...
 $ AirTime             : num  324 327 344 325 334 341 347 318 337 332 ...
 $ Flights             : num  1 1 1 1 1 1 1 1 1 1 ...
 $ Distance            : num  2556 2556 2556 2556 2556 ...
 $ DistanceGroup       : int  11 11 11 11 11 11 11 11 11 11 ...
 $ CarrierDelay        : num  NA NA NA NA NA NA NA NA 59 NA ...
 $ WeatherDelay        : num  NA NA NA NA NA NA NA NA 0 NA ...
 $ NASDelay            : num  NA NA NA NA NA NA NA NA 0 NA ...
 $ SecurityDelay       : num  NA NA NA NA NA NA NA NA 0 NA ...
 $ LateAircraftDelay   : num  NA NA NA NA NA NA NA NA 0 NA ...
 $ FirstDepTime        : int  NA NA NA NA NA NA NA NA NA NA ...
 $ TotalAddGTime       : num  NA NA NA NA NA NA NA NA NA NA ...
 $ LongestAddGTime     : num  NA NA NA NA NA NA NA NA NA NA ...
 $ DivAirportLandings  : int  0 0 0 0 0 0 0 0 0 0 ...
 $ DivReachedDest      : num  NA NA NA NA NA NA NA NA NA NA ...
 $ DivActualElapsedTime: num  NA NA NA NA NA NA NA NA NA NA ...
 $ DivArrDelay         : num  NA NA NA NA NA NA NA NA NA NA ...
 $ DivDistance         : num  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1Airport         : chr  "" "" "" "" ...
 $ Div1AirportID       : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1AirportSeqID    : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1WheelsOn        : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1TotalGTime      : num  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1LongestGTime    : num  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1WheelsOff       : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div1TailNum         : chr  "" "" "" "" ...
 $ Div2Airport         : chr  "" "" "" "" ...
 $ Div2AirportID       : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div2AirportSeqID    : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div2WheelsOn        : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div2TotalGTime      : num  NA NA NA NA NA NA NA NA NA NA ...
 $ Div2LongestGTime    : num  NA NA NA NA NA NA NA NA NA NA ...
 $ Div2WheelsOff       : int  NA NA NA NA NA NA NA NA NA NA ...
 $ Div2TailNum         : chr  "" "" "" "" ...
 $ Div3Airport         : logi  NA NA NA NA NA NA ...
 $ Div3AirportID       : logi  NA NA NA NA NA NA ...
 $ Div3AirportSeqID    : logi  NA NA NA NA NA NA ...
 $ Div3WheelsOn        : logi  NA NA NA NA NA NA ...
 $ Div3TotalGTime      : logi  NA NA NA NA NA NA ...
 $ Div3LongestGTime    : logi  NA NA NA NA NA NA ...
 $ Div3WheelsOff       : logi  NA NA NA NA NA NA ...
 $ Div3TailNum         : logi  NA NA NA NA NA NA ...
 $ Div4Airport         : logi  NA NA NA NA NA NA ...
 $ Div4AirportID       : logi  NA NA NA NA NA NA ...
 $ Div4AirportSeqID    : logi  NA NA NA NA NA NA ...
 $ Div4WheelsOn        : logi  NA NA NA NA NA NA ...
 $ Div4TotalGTime      : logi  NA NA NA NA NA NA ...
 $ Div4LongestGTime    : logi  NA NA NA NA NA NA ...
  [list output truncated]

Question 3

missing_values <- sum(is.na(OnTimePerformance$Div2WheelsOff))
print(missing_values)
[1] 570122

Question 4

avg_dep_delay <- OnTimePerformance %>%
  group_by(UniqueCarrier) %>%  
  summarise(avg_dep_delay = mean(DepDelay, na.rm = TRUE)) %>% 
  arrange(desc(avg_dep_delay))
print(avg_dep_delay)

Answer: B6

Question 5

install.packages("jsonlite")
library(jsonlite)
url <- ("https://min-api.cryptocompare.com/data/v2/histoday?fsym=BTC&tsym=USD&limit=100")

data <- fromJSON(url)

btc_data <- as.data.frame(data$Data$Data)

max_close_price <- max(btc_data$close, na.rm = TRUE)

print(max_close_price)
[1] 106155.6
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