odev4

a <- 12 + 6
a

## [1] 18

b<- a + 45
b

## [1] 63

c<- b/a
c

## [1] 3.5

d<- b*c
d

## [1] 220.5

osman<- c(1,2,3,4)
osman

## [1] 1 2 3 4

ali<- c("ahmet","mehmet","mustafa")
ali

## [1] "ahmet"   "mehmet"  "mustafa"

myvec<-c(birici<-osman,ikinci<-ali)
myvec

## [1] "1"       "2"       "3"       "4"       "ahmet"   "mehmet"  "mustafa"

library(wooldridge)

## Warning: package 'wooldridge' was built under R version 4.1.3

data(intdef)
head(intdef)

##   year   i3  inf  rec  out        def i3_1 inf_1      def_1        ci3 cinf
## 1 1948 1.04  8.1 16.2 11.6 -4.6000004   NA    NA         NA         NA   NA
## 2 1949 1.10 -1.2 14.5 14.3 -0.1999998 1.04   8.1 -4.6000004 0.06000006 -9.3
## 3 1950 1.22  1.3 14.4 15.6  1.2000008 1.10  -1.2 -0.1999998 0.12000000  2.5
## 4 1951 1.55  7.9 16.1 14.2 -1.9000006 1.22   1.3  1.2000008 0.32999992  6.6
## 5 1952 1.77  1.9 19.0 19.4  0.3999996 1.55   7.9 -1.9000006 0.22000003 -6.0
## 6 1953 1.93  0.8 18.7 20.4  1.6999989 1.77   1.9  0.3999996 0.15999997 -1.1
##        cdef y77
## 1        NA   0
## 2  4.400001   0
## 3  1.400001   0
## 4 -3.100001   0
## 5  2.300000   0
## 6  1.299999   0

?intdef

## starting httpd help server ... done

plot(inf~year, data = intdef)

plot( intdef$inf ~ intdef$year)

attach(intdef)
plot(inf ~ year)

detach(intdef)
ilkmodel<- lm(intdef$i3 ~ intdef$inf)
summary(ilkmodel)

## 
## Call:
## lm(formula = intdef$i3 ~ intdef$inf)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -6.5689 -1.0385  0.0678  0.8962  5.0119 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  2.42032    0.46328   5.224 2.88e-06 ***
## intdef$inf   0.64056    0.09425   6.797 8.81e-09 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 2.125 on 54 degrees of freedom
## Multiple R-squared:  0.461,  Adjusted R-squared:  0.4511 
## F-statistic: 46.19 on 1 and 54 DF,  p-value: 8.812e-09

matris1 <- matrix(c(1,2,3,4,5,6), nrow=2 , ncol=3)
matris1

##      [,1] [,2] [,3]
## [1,]    1    3    5
## [2,]    2    4    6

matris1[1,]

## [1] 1 3 5

matris1[,2]

## [1] 3 4

matris1[1,,  drop = FALSE]

##      [,1] [,2] [,3]
## [1,]    1    3    5

rownames(matris1) <- c("a","b")
matris1

##   [,1] [,2] [,3]
## a    1    3    5
## b    2    4    6

colnames(matris1) <- c("c","d","e")
matris1

##   c d e
## a 1 3 5
## b 2 4 6