Activity 4

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plot(cars)

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#Addition
2+3

[1] 5

#Subtraction
2-5

[1] -3

#Exponents
5^3

[1] 125

#Log
log10(10)

[1] 1

log(2.72,base = 2.72)

[1] 1

#Question_1: Compute the log base 5 of 10 and the log of 10.
log10(10)

[1] 1

log10(100)

[1] 2

log(10, base = 5)

[1] 1.430677

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#Batting Average=(No. of Hits)/(No. of At Bats)
#What is the batting average of a player that bats 29 hits in 112 at bats?
BA=(29)/(112)
BA

[1] 0.2589286

BA=(42)/(212)
Batting_Average=round(BA,digits = 3)
Batting_Average

[1] 0.198

#Question_2:What is the batting average of a player that bats 42 hits in 212 at bats?
#On Base Percentage
#OBP=(H+BB+HBP)/(At Bats+BB+HBP+SF)
#Let us compute the OBP for a player with the following general stats
#AB=515,H=172,BB=84,HBP=5,SF=6
OBP=(172+84+5)/(515+84+5+6)
OBP

[1] 0.4278689

On_Base_Percentage=round(OBP,digits = 3)
On_Base_Percentage

[1] 0.428

#Question_3:Compute the OBP for a player with the following general stats:
#OBP=(H+BB+HBP)/(At Bats+BB+HBP+SF)
#AB=565,H=156,BB=65,HBP=3,SF=7
OBP=(156+65+3)/(565+65+3+7)
OBP

[1] 0.35

On_Base_Percentage=round(OBP,digits = 3)
On_Base_Percentage

[1] 0.35

3 == 8# Does 3 equals 8?

[1] FALSE

3 != 8# Is 3 different from 8?

[1] TRUE

3 <= 8# Is 3 less than or equal to 8?

[1] TRUE

3>4

[1] FALSE

# Logical Conjunction (and)
TRUE & FALSE #True AND False

[1] FALSE

# Negation
! FALSE # Not False

[1] TRUE

# Combination of statements
2 < 3 | 1 == 5 # 2<3 is True, 1==5 is False, True OR False is True

[1] TRUE

Total_Bases <- 6 + 5
Total_Bases*3

[1] 33

ls()

 [1] "BA"                 "Batting_Average"    "game_day"          
 [4] "getMode"            "hits_per_9innings"  "OBP"               
 [7] "On_Base_Percentage" "pitches_by_innings" "runs_per_9innings" 
[10] "strikes_by_innings" "Total_Bases"       

rm(Total_Bases)

pitches_by_innings <- c(12, 15, 10, 20, 10) 
pitches_by_innings

[1] 12 15 10 20 10

strikes_by_innings <- c(9, 12, 6, 14, 9)
strikes_by_innings

[1]  9 12  6 14  9

#Question_4: Define two vectors,runs_per_9innings and hits_per_9innings, each with five elements. 
runs_per_9innings<-c(2,5,7,11,13)
hits_per_9innings<-c(11,13,16,18,19)

# replicate function
rep(2, 5)

[1] 2 2 2 2 2

rep(1,4)

[1] 1 1 1 1

# consecutive numbers
1:5

[1] 1 2 3 4 5

2:10

[1]  2  3  4  5  6  7  8  9 10

# sequence from 1 to 10 with a step of 2
seq(1, 10, by=2)

[1] 1 3 5 7 9

seq(2,13,by=3)

[1]  2  5  8 11

seq(2,13,by=3)

[1]  2  5  8 11

# add vectors
pitches_by_innings+strikes_by_innings

[1] 21 27 16 34 19

# compare vectors
pitches_by_innings == strikes_by_innings

[1] FALSE FALSE FALSE FALSE FALSE

# find length of vector
length(pitches_by_innings)

[1] 5

# find minimum value in vector
min(pitches_by_innings)

[1] 10

# find average value in vector
mean(pitches_by_innings)

[1] 13.4

# If you want to get the first element:
pitches_by_innings[1]

[1] 12

#Question_5: Get the first element of hits_per_9innings.
hits_per_9innings[1]

[1] 11

#Question_6: Get the last element of hits_per_9innings.
hits_per_9innings[length(hits_per_9innings)]

[1] 19

# Function to find the mode, i.e. most frequent value
getMode <- function(x) {
     ux <- unique(x)
     ux[which.max(tabulate(match(x, ux)))]
 }

#Question_7: Find the most frequent value of hits_per_9innings.
getMode(hits_per_9innings)

[1] 11

#Question_8: Summarize the following survey with the `table()` command:
#What is your favorite day of the week to watch baseball? A total of 10 fans submitted this survey.
#Saturday, Saturday, Sunday, Monday, Saturday,Tuesday, Sunday, Friday, Friday, Monday
game_day<-c("Saturday", "Saturday", "Sunday", "Monday", "Saturday","Tuesday", "Sunday", "Friday", "Friday", "Monday")

table(game_day)

game_day
  Friday   Monday Saturday   Sunday  Tuesday 
       2        2        3        2        1 

#Question_9: What is the most frequent answer recorded in the survey? Use the GetMode function to compute results. 
getMode(game_day)

[1] "Saturday"