#ĐỌc dữ liệu gói gapminder

library(gapminder)
data(gapminder)
vn = subset(gapminder, country == "Vietnam")

library(lessR)
## 
## lessR 4.4.5                         feedback: gerbing@pdx.edu 
## --------------------------------------------------------------
## > d <- Read("")  Read data file, many formats available, e.g., Excel
##   d is default data frame, data= in analysis routines optional
## 
## Many examples of reading, writing, and manipulating data, 
## graphics, testing means and proportions, regression, factor analysis,
## customization, forecasting, and aggregation from pivot tables
##   Enter: browseVignettes("lessR")
## 
## View lessR updates, now including time series forecasting
##   Enter: news(package="lessR")
## 
## Interactive data analysis
##   Enter: interact()
Plot(lifeExp, year, data = vn, xlab = "Life expectancy (years)", ylab = "Year")

## 
## >>> Suggestions  or  enter: style(suggest=FALSE)
## Plot(lifeExp, year, enhance=TRUE)  # many options
## Plot(lifeExp, year, color="red")  # exterior edge color of points
## Plot(lifeExp, year, fit="lm", fit_se=c(.90,.99))  # fit line, stnd errors
## Plot(lifeExp, year, out_cut=.10)  # label top 10% from center as outliers 
## 
## 
## >>> Pearson's product-moment correlation 
##  
## Number of paired values with neither missing, n = 12 
## Sample Correlation of lifeExp and year: r = 0.995 
##   
## Hypothesis Test of 0 Correlation:  t = 30.569,  df = 10,  p-value = 0.000 
## 95% Confidence Interval for Correlation:  0.981 to 0.999 
##

xác định tuổi thọ

library(lessR)
m.1 = lm(lifeExp ~ year, data = vn)
summary(m.1)
## 
## Call:
## lm(formula = lifeExp ~ year, data = vn)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -2.1884 -0.5840  0.1335  0.7396  1.7873 
## 
## Coefficients:
##                Estimate  Std. Error t value        Pr(>|t|)    
## (Intercept) -1271.98315    43.49240  -29.25 0.0000000000510 ***
## year            0.67162     0.02197   30.57 0.0000000000329 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.314 on 10 degrees of freedom
## Multiple R-squared:  0.9894, Adjusted R-squared:  0.9884 
## F-statistic: 934.5 on 1 and 10 DF,  p-value: 0.00000000003289
m.2 = Regression(lifeExp ~ year, data = vn)

# xác định tuổi thọ người

library(lessR)
library(gapminder)
vn <- subset(gapminder, country == "Vietnam")
m.2 = Regression(lifeExp ~ year, data = vn)