library(readxl)
AgeHeight <- read_excel("C:/Users/jawii/Downloads/AgeHeight.xlsx")
ImHeight= lm(height~age+no_siblings,data=AgeHeight)
summary(ImHeight)
## 
## Call:
## lm(formula = height ~ age + no_siblings, data = AgeHeight)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -0.26297 -0.22462 -0.02021  0.16102  0.49752 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 64.90554    0.53526 121.260 8.96e-16 ***
## age          0.63751    0.02340  27.249 5.85e-10 ***
## no_siblings -0.01772    0.04735  -0.374    0.717    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.2677 on 9 degrees of freedom
## Multiple R-squared:  0.9889, Adjusted R-squared:  0.9865 
## F-statistic: 402.2 on 2 and 9 DF,  p-value: 1.576e-09
library(readr)
library(psych)
## Warning: package 'psych' was built under R version 4.3.3
insurance <- read_csv("C:/Users/jawii/Downloads/insurance.csv")
## Rows: 1338 Columns: 7
## ── Column specification ────────────────────────────────────────────────────────
## Delimiter: ","
## chr (3): sex, smoker, region
## dbl (4): age, bmi, children, charges
## 
## 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.
str(insurance)
## spc_tbl_ [1,338 × 7] (S3: spec_tbl_df/tbl_df/tbl/data.frame)
##  $ age     : num [1:1338] 19 18 28 33 32 31 46 37 37 60 ...
##  $ sex     : chr [1:1338] "female" "male" "male" "male" ...
##  $ bmi     : num [1:1338] 27.9 33.8 33 22.7 28.9 ...
##  $ children: num [1:1338] 0 1 3 0 0 0 1 3 2 0 ...
##  $ smoker  : chr [1:1338] "yes" "no" "no" "no" ...
##  $ region  : chr [1:1338] "southwest" "southeast" "southeast" "northwest" ...
##  $ charges : num [1:1338] 16885 1726 4449 21984 3867 ...
##  - attr(*, "spec")=
##   .. cols(
##   ..   age = col_double(),
##   ..   sex = col_character(),
##   ..   bmi = col_double(),
##   ..   children = col_double(),
##   ..   smoker = col_character(),
##   ..   region = col_character(),
##   ..   charges = col_double()
##   .. )
##  - attr(*, "problems")=<externalptr>
hist(insurance$charges)

prop_table <- prop.table(table(insurance$smoker))
prop_table
## 
##        no       yes 
## 0.7952167 0.2047833
cor(insurance[c('age','bmi','children', 'charges')])
##                age       bmi   children    charges
## age      1.0000000 0.1092719 0.04246900 0.29900819
## bmi      0.1092719 1.0000000 0.01275890 0.19834097
## children 0.0424690 0.0127589 1.00000000 0.06799823
## charges  0.2990082 0.1983410 0.06799823 1.00000000
pairs.panels(insurance[c('age','bmi','children', 'charges')])

ins_model<-lm(charges~age+children+bmi+sex+smoker+region,data=insurance)
summary(ins_model)
## 
## Call:
## lm(formula = charges ~ age + children + bmi + sex + smoker + 
##     region, data = insurance)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -11304.9  -2848.1   -982.1   1393.9  29992.8 
## 
## Coefficients:
##                 Estimate Std. Error t value Pr(>|t|)    
## (Intercept)     -11938.5      987.8 -12.086  < 2e-16 ***
## age                256.9       11.9  21.587  < 2e-16 ***
## children           475.5      137.8   3.451 0.000577 ***
## bmi                339.2       28.6  11.860  < 2e-16 ***
## sexmale           -131.3      332.9  -0.394 0.693348    
## smokeryes        23848.5      413.1  57.723  < 2e-16 ***
## regionnorthwest   -353.0      476.3  -0.741 0.458769    
## regionsoutheast  -1035.0      478.7  -2.162 0.030782 *  
## regionsouthwest   -960.0      477.9  -2.009 0.044765 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 6062 on 1329 degrees of freedom
## Multiple R-squared:  0.7509, Adjusted R-squared:  0.7494 
## F-statistic: 500.8 on 8 and 1329 DF,  p-value: < 2.2e-16
insurance$bmi <- ifelse(insurance$bmi > 30, 1, 0)
charges~bmi30*smoker
## charges ~ bmi30 * smoker