This will contain the future R coding exercise.

Loading packages and calling data

#Load Packages: dlslabs and tidyverse 
library("dslabs")
library("tidyverse")
## ── Attaching packages ─────────────────────────────────────── tidyverse 1.3.1 ──
## ✓ ggplot2 3.3.5     ✓ purrr   0.3.4
## ✓ tibble  3.1.5     ✓ dplyr   1.0.7
## ✓ tidyr   1.1.4     ✓ stringr 1.4.0
## ✓ readr   1.4.0     ✓ forcats 0.5.1
## ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
#Help for gapminder data
help(gapminder)
#Overview data structure
str(gapminder)
## 'data.frame':    10545 obs. of  9 variables:
##  $ country         : Factor w/ 185 levels "Albania","Algeria",..: 1 2 3 4 5 6 7 8 9 10 ...
##  $ year            : int  1960 1960 1960 1960 1960 1960 1960 1960 1960 1960 ...
##  $ infant_mortality: num  115.4 148.2 208 NA 59.9 ...
##  $ life_expectancy : num  62.9 47.5 36 63 65.4 ...
##  $ fertility       : num  6.19 7.65 7.32 4.43 3.11 4.55 4.82 3.45 2.7 5.57 ...
##  $ population      : num  1636054 11124892 5270844 54681 20619075 ...
##  $ gdp             : num  NA 1.38e+10 NA NA 1.08e+11 ...
##  $ continent       : Factor w/ 5 levels "Africa","Americas",..: 4 1 1 2 2 3 2 5 4 3 ...
##  $ region          : Factor w/ 22 levels "Australia and New Zealand",..: 19 11 10 2 15 21 2 1 22 21 ...
#Get data summary
summary(gapminder)
##                 country           year      infant_mortality life_expectancy
##  Albania            :   57   Min.   :1960   Min.   :  1.50   Min.   :13.20  
##  Algeria            :   57   1st Qu.:1974   1st Qu.: 16.00   1st Qu.:57.50  
##  Angola             :   57   Median :1988   Median : 41.50   Median :67.54  
##  Antigua and Barbuda:   57   Mean   :1988   Mean   : 55.31   Mean   :64.81  
##  Argentina          :   57   3rd Qu.:2002   3rd Qu.: 85.10   3rd Qu.:73.00  
##  Armenia            :   57   Max.   :2016   Max.   :276.90   Max.   :83.90  
##  (Other)            :10203                  NA's   :1453                    
##    fertility       population             gdp               continent   
##  Min.   :0.840   Min.   :3.124e+04   Min.   :4.040e+07   Africa  :2907  
##  1st Qu.:2.200   1st Qu.:1.333e+06   1st Qu.:1.846e+09   Americas:2052  
##  Median :3.750   Median :5.009e+06   Median :7.794e+09   Asia    :2679  
##  Mean   :4.084   Mean   :2.701e+07   Mean   :1.480e+11   Europe  :2223  
##  3rd Qu.:6.000   3rd Qu.:1.523e+07   3rd Qu.:5.540e+10   Oceania : 684  
##  Max.   :9.220   Max.   :1.376e+09   Max.   :1.174e+13                  
##  NA's   :187     NA's   :185         NA's   :2972                       
##              region    
##  Western Asia   :1026  
##  Eastern Africa : 912  
##  Western Africa : 912  
##  Caribbean      : 741  
##  South America  : 684  
##  Southern Europe: 684  
##  (Other)        :5586
#Determine gapminder type of object
class(gapminder)
## [1] "data.frame"

Processing Data (Target Variable)

#Create a new object "africadata" in order to analyzed African countries
africadata <- gapminder %>% filter(continent=="Africa")
#Overview data structure
str(africadata)
## 'data.frame':    2907 obs. of  9 variables:
##  $ country         : Factor w/ 185 levels "Albania","Algeria",..: 2 3 18 22 26 27 29 31 32 33 ...
##  $ year            : int  1960 1960 1960 1960 1960 1960 1960 1960 1960 1960 ...
##  $ infant_mortality: num  148 208 187 116 161 ...
##  $ life_expectancy : num  47.5 36 38.3 50.3 35.2 ...
##  $ fertility       : num  7.65 7.32 6.28 6.62 6.29 6.95 5.65 6.89 5.84 6.25 ...
##  $ population      : num  11124892 5270844 2431620 524029 4829291 ...
##  $ gdp             : num  1.38e+10 NA 6.22e+08 1.24e+08 5.97e+08 ...
##  $ continent       : Factor w/ 5 levels "Africa","Americas",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ region          : Factor w/ 22 levels "Australia and New Zealand",..: 11 10 20 17 20 5 10 20 10 10 ...
#Get data summary
summary(africadata)
##          country          year      infant_mortality life_expectancy
##  Algeria     :  57   Min.   :1960   Min.   : 11.40   Min.   :13.20  
##  Angola      :  57   1st Qu.:1974   1st Qu.: 62.20   1st Qu.:48.23  
##  Benin       :  57   Median :1988   Median : 93.40   Median :53.98  
##  Botswana    :  57   Mean   :1988   Mean   : 95.12   Mean   :54.38  
##  Burkina Faso:  57   3rd Qu.:2002   3rd Qu.:124.70   3rd Qu.:60.10  
##  Burundi     :  57   Max.   :2016   Max.   :237.40   Max.   :77.60  
##  (Other)     :2565                  NA's   :226                     
##    fertility       population             gdp               continent   
##  Min.   :1.500   Min.   :    41538   Min.   :4.659e+07   Africa  :2907  
##  1st Qu.:5.160   1st Qu.:  1605232   1st Qu.:8.373e+08   Americas:   0  
##  Median :6.160   Median :  5570982   Median :2.448e+09   Asia    :   0  
##  Mean   :5.851   Mean   : 12235961   Mean   :9.346e+09   Europe  :   0  
##  3rd Qu.:6.860   3rd Qu.: 13888152   3rd Qu.:6.552e+09   Oceania :   0  
##  Max.   :8.450   Max.   :182201962   Max.   :1.935e+11                  
##  NA's   :51      NA's   :51          NA's   :637                        
##                        region   
##  Eastern Africa           :912  
##  Western Africa           :912  
##  Middle Africa            :456  
##  Northern Africa          :342  
##  Southern Africa          :285  
##  Australia and New Zealand:  0  
##  (Other)                  :  0
#Create new objects containing infant_mortality and life_expectancy
mortality_lifexp <- africadata %>% select(infant_mortality, life_expectancy)

#Create new objects containing population and life_expectancy
population_lifexp <- africadata %>% select(population , life_expectancy)

#Overview data structure
str(mortality_lifexp)
## 'data.frame':    2907 obs. of  2 variables:
##  $ infant_mortality: num  148 208 187 116 161 ...
##  $ life_expectancy : num  47.5 36 38.3 50.3 35.2 ...
str(population_lifexp)
## 'data.frame':    2907 obs. of  2 variables:
##  $ population     : num  11124892 5270844 2431620 524029 4829291 ...
##  $ life_expectancy: num  47.5 36 38.3 50.3 35.2 ...
#Get data summary
summary(mortality_lifexp)
##  infant_mortality life_expectancy
##  Min.   : 11.40   Min.   :13.20  
##  1st Qu.: 62.20   1st Qu.:48.23  
##  Median : 93.40   Median :53.98  
##  Mean   : 95.12   Mean   :54.38  
##  3rd Qu.:124.70   3rd Qu.:60.10  
##  Max.   :237.40   Max.   :77.60  
##  NA's   :226
summary(population_lifexp)
##    population        life_expectancy
##  Min.   :    41538   Min.   :13.20  
##  1st Qu.:  1605232   1st Qu.:48.23  
##  Median :  5570982   Median :53.98  
##  Mean   : 12235961   Mean   :54.38  
##  3rd Qu.: 13888152   3rd Qu.:60.10  
##  Max.   :182201962   Max.   :77.60  
##  NA's   :51

Visualization: Plot creation of the new objects/variables

#Plot life_expectacy vs Infant_mortality
ggplot(mortality_lifexp, aes(infant_mortality, life_expectancy)) + geom_point()
## Warning: Removed 226 rows containing missing values (geom_point).

#This plot shows a negative correlation between infant mortality and life expectancy. 226 rows were removed due to missing values

#Plot Life_expectancy Vs Population(log scale)
ggplot(population_lifexp, aes(population, life_expectancy)) + geom_point() + scale_x_log10()
## Warning: Removed 51 rows containing missing values (geom_point).

#This plot shows a positive correlation between Population and Life expectancy. According with africadata, the frame time when the data was collected was between 1960 to 2016, during this time population size and life expectacy got increse. This is the reason of the streaks. ** 51 rows were removed from the plot due to missing values.

Cleaning Data

#Finding the year have missing data for infant mortality
africadata_na <- africadata %>% select(year, infant_mortality) %>% filter(is.na(infant_mortality))
africadata_na
##     year infant_mortality
## 1   1960               NA
## 2   1960               NA
## 3   1960               NA
## 4   1960               NA
## 5   1960               NA
## 6   1960               NA
## 7   1960               NA
## 8   1960               NA
## 9   1960               NA
## 10  1960               NA
## 11  1961               NA
## 12  1961               NA
## 13  1961               NA
## 14  1961               NA
## 15  1961               NA
## 16  1961               NA
## 17  1961               NA
## 18  1961               NA
## 19  1961               NA
## 20  1961               NA
## 21  1961               NA
## 22  1961               NA
## 23  1961               NA
## 24  1961               NA
## 25  1961               NA
## 26  1961               NA
## 27  1961               NA
## 28  1962               NA
## 29  1962               NA
## 30  1962               NA
## 31  1962               NA
## 32  1962               NA
## 33  1962               NA
## 34  1962               NA
## 35  1962               NA
## 36  1962               NA
## 37  1962               NA
## 38  1962               NA
## 39  1962               NA
## 40  1962               NA
## 41  1962               NA
## 42  1962               NA
## 43  1962               NA
## 44  1963               NA
## 45  1963               NA
## 46  1963               NA
## 47  1963               NA
## 48  1963               NA
## 49  1963               NA
## 50  1963               NA
## 51  1963               NA
## 52  1963               NA
## 53  1963               NA
## 54  1963               NA
## 55  1963               NA
## 56  1963               NA
## 57  1963               NA
## 58  1963               NA
## 59  1963               NA
## 60  1964               NA
## 61  1964               NA
## 62  1964               NA
## 63  1964               NA
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## 65  1964               NA
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## 68  1964               NA
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## 70  1964               NA
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## 72  1964               NA
## 73  1964               NA
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## 75  1965               NA
## 76  1965               NA
## 77  1965               NA
## 78  1965               NA
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## 80  1965               NA
## 81  1965               NA
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## 83  1965               NA
## 84  1965               NA
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## 86  1965               NA
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## 88  1965               NA
## 89  1966               NA
## 90  1966               NA
## 91  1966               NA
## 92  1966               NA
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## 94  1966               NA
## 95  1966               NA
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## 100 1966               NA
## 101 1966               NA
## 102 1967               NA
## 103 1967               NA
## 104 1967               NA
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## 106 1967               NA
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## 110 1967               NA
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## 113 1968               NA
## 114 1968               NA
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## 116 1968               NA
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## 118 1968               NA
## 119 1968               NA
## 120 1968               NA
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## 122 1968               NA
## 123 1968               NA
## 124 1969               NA
## 125 1969               NA
## 126 1969               NA
## 127 1969               NA
## 128 1969               NA
## 129 1969               NA
## 130 1969               NA
## 131 1970               NA
## 132 1970               NA
## 133 1970               NA
## 134 1970               NA
## 135 1970               NA
## 136 1971               NA
## 137 1971               NA
## 138 1971               NA
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## 140 1971               NA
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## 142 1972               NA
## 143 1972               NA
## 144 1972               NA
## 145 1972               NA
## 146 1972               NA
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## 149 1973               NA
## 150 1973               NA
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## 152 1973               NA
## 153 1973               NA
## 154 1974               NA
## 155 1974               NA
## 156 1974               NA
## 157 1974               NA
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## 160 1975               NA
## 161 1975               NA
## 162 1975               NA
## 163 1975               NA
## 164 1976               NA
## 165 1976               NA
## 166 1976               NA
## 167 1977               NA
## 168 1977               NA
## 169 1977               NA
## 170 1978               NA
## 171 1978               NA
## 172 1979               NA
## 173 1979               NA
## 174 1980               NA
## 175 1981               NA
## 176 2016               NA
## 177 2016               NA
## 178 2016               NA
## 179 2016               NA
## 180 2016               NA
## 181 2016               NA
## 182 2016               NA
## 183 2016               NA
## 184 2016               NA
## 185 2016               NA
## 186 2016               NA
## 187 2016               NA
## 188 2016               NA
## 189 2016               NA
## 190 2016               NA
## 191 2016               NA
## 192 2016               NA
## 193 2016               NA
## 194 2016               NA
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## 196 2016               NA
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## 198 2016               NA
## 199 2016               NA
## 200 2016               NA
## 201 2016               NA
## 202 2016               NA
## 203 2016               NA
## 204 2016               NA
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## 210 2016               NA
## 211 2016               NA
## 212 2016               NA
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## 214 2016               NA
## 215 2016               NA
## 216 2016               NA
## 217 2016               NA
## 218 2016               NA
## 219 2016               NA
## 220 2016               NA
## 221 2016               NA
## 222 2016               NA
## 223 2016               NA
## 224 2016               NA
## 225 2016               NA
## 226 2016               NA
#1960 - 1981 and 2016 have missing data.

#To avoid missing data a new variable will be created only with data from year 2000
africadata_2000 <- africadata %>% filter(year==2000)

#Overview data structure
str(africadata_2000)
## 'data.frame':    51 obs. of  9 variables:
##  $ country         : Factor w/ 185 levels "Albania","Algeria",..: 2 3 18 22 26 27 29 31 32 33 ...
##  $ year            : int  2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 ...
##  $ infant_mortality: num  33.9 128.3 89.3 52.4 96.2 ...
##  $ life_expectancy : num  73.3 52.3 57.2 47.6 52.6 46.7 54.3 68.4 45.3 51.5 ...
##  $ fertility       : num  2.51 6.84 5.98 3.41 6.59 7.06 5.62 3.7 5.45 7.35 ...
##  $ population      : num  31183658 15058638 6949366 1736579 11607944 ...
##  $ gdp             : num  5.48e+10 9.13e+09 2.25e+09 5.63e+09 2.61e+09 ...
##  $ continent       : Factor w/ 5 levels "Africa","Americas",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ region          : Factor w/ 22 levels "Australia and New Zealand",..: 11 10 20 17 20 5 10 20 10 10 ...
#Get data summary
summary(africadata_2000)
##          country        year      infant_mortality life_expectancy
##  Algeria     : 1   Min.   :2000   Min.   : 12.30   Min.   :37.60  
##  Angola      : 1   1st Qu.:2000   1st Qu.: 60.80   1st Qu.:51.75  
##  Benin       : 1   Median :2000   Median : 80.30   Median :54.30  
##  Botswana    : 1   Mean   :2000   Mean   : 78.93   Mean   :56.36  
##  Burkina Faso: 1   3rd Qu.:2000   3rd Qu.:103.30   3rd Qu.:60.00  
##  Burundi     : 1   Max.   :2000   Max.   :143.30   Max.   :75.00  
##  (Other)     :45                                                  
##    fertility       population             gdp               continent 
##  Min.   :1.990   Min.   :    81154   Min.   :2.019e+08   Africa  :51  
##  1st Qu.:4.150   1st Qu.:  2304687   1st Qu.:1.274e+09   Americas: 0  
##  Median :5.550   Median :  8799165   Median :3.238e+09   Asia    : 0  
##  Mean   :5.156   Mean   : 15659800   Mean   :1.155e+10   Europe  : 0  
##  3rd Qu.:5.960   3rd Qu.: 17391242   3rd Qu.:8.654e+09   Oceania : 0  
##  Max.   :7.730   Max.   :122876723   Max.   :1.329e+11                
##                                                                       
##                        region  
##  Eastern Africa           :16  
##  Western Africa           :16  
##  Middle Africa            : 8  
##  Northern Africa          : 6  
##  Southern Africa          : 5  
##  Australia and New Zealand: 0  
##  (Other)                  : 0

Visualization: Plotting clean data

#Plots using only data from year 2000
#Plots will be showed the variable correlation for year 2000
#Plot life expectancy vs infant mortality 
ggplot(africadata_2000, aes(infant_mortality, life_expectancy)) + geom_point()

#The plot shows negative correlation between infant mortality and life expectancy.

#Plot Life_expectancy Vs Population(log scale)
ggplot(africadata_2000, aes(population, life_expectancy)) + geom_point() + scale_x_log10()

#The  plot does not shows a specific relationship between the population size and the life expectancy.

Fitting linear regression

#We will use lm  function for fit a lineal model with infant mortality as a predictor
fit1<- lm(life_expectancy ~ infant_mortality, data=africadata_2000)

#We will use lm  function for fit a lineal model with population as a predictor
fit2<- lm(life_expectancy ~ population, data=africadata_2000)

#Get the summary
summary(fit1)
## 
## Call:
## lm(formula = life_expectancy ~ infant_mortality, data = africadata_2000)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -22.6651  -3.7087   0.9914   4.0408   8.6817 
## 
## Coefficients:
##                  Estimate Std. Error t value Pr(>|t|)    
## (Intercept)      71.29331    2.42611  29.386  < 2e-16 ***
## infant_mortality -0.18916    0.02869  -6.594 2.83e-08 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 6.221 on 49 degrees of freedom
## Multiple R-squared:  0.4701, Adjusted R-squared:  0.4593 
## F-statistic: 43.48 on 1 and 49 DF,  p-value: 2.826e-08
summary(fit2)
## 
## Call:
## lm(formula = life_expectancy ~ population, data = africadata_2000)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -18.429  -4.602  -2.568   3.800  18.802 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 5.593e+01  1.468e+00  38.097   <2e-16 ***
## population  2.756e-08  5.459e-08   0.505    0.616    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 8.524 on 49 degrees of freedom
## Multiple R-squared:  0.005176,   Adjusted R-squared:  -0.01513 
## F-statistic: 0.2549 on 1 and 49 DF,  p-value: 0.6159
#Based on the outcomes of the two models and using their p-values, we can conclude that the infant mortality as a predictor (p-value<0.05) shows a significant correlation with life expectancy. The model with population as a predictor has a p-value>0.05, suggesting that is not a good predictor of life expectancy.

Part 2 - Data Manipulation

Here we are going to look at population and GDP in India to see if they are good indicators of life expectancy.

library(broom)

#This filters the data so it only holds data from India
Indiadata <- filter(gapminder, country=="India")

Next we create two data frames containing the variables we are looking at.

IndiaPOPLE <- select(Indiadata, population, life_expectancy)

IndiaGDPLE <- select(Indiadata, gdp, life_expectancy)

summary(IndiaPOPLE)
##    population        life_expectancy
##  Min.   :4.497e+08   Min.   :41.26  
##  1st Qu.:6.039e+08   1st Qu.:51.53  
##  Median :8.261e+08   Median :57.65  
##  Mean   :8.453e+08   Mean   :56.58  
##  3rd Qu.:1.076e+09   3rd Qu.:62.30  
##  Max.   :1.311e+09   Max.   :67.50  
##  NA's   :1
summary(IndiaGDPLE)
##       gdp            life_expectancy
##  Min.   :8.104e+10   Min.   :41.26  
##  1st Qu.:1.242e+11   1st Qu.:51.53  
##  Median :2.120e+11   Median :57.65  
##  Mean   :3.155e+11   Mean   :56.58  
##  3rd Qu.:4.298e+11   3rd Qu.:62.30  
##  Max.   :1.040e+12   Max.   :67.50  
##  NA's   :5

Part 2 - Plotting

ggplot(IndiaPOPLE, aes(x = population, y = life_expectancy)) +
      geom_point() +
      xlab("Population") +
      ylab("Life Expectancy")
## Warning: Removed 1 rows containing missing values (geom_point).

ggplot(IndiaGDPLE, aes(x = gdp, y = life_expectancy)) +
      geom_point() +
      xlab("GDP") +
      ylab("Life Expectancy")
## Warning: Removed 5 rows containing missing values (geom_point).

Both of these have positive associations, the first graph with population and life expectancy in particular has a more stable increase over time, whereas the GDP graph has a more exponential increase.

Part 2 - Linear Models

#These create the linear models with life expectancy as the outcome variable and population/gdp as the predictor

fit3 <- lm(population ~ life_expectancy, IndiaPOPLE)

fit4 <- lm(gdp ~ life_expectancy, IndiaGDPLE)



summary(fit3)
## 
## Call:
## lm(formula = population ~ life_expectancy, data = IndiaPOPLE)
## 
## Residuals:
##        Min         1Q     Median         3Q        Max 
## -101866846  -57587094    2456008   51590062  146640137 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)     -1.176e+09  7.078e+07  -16.61   <2e-16 ***
## life_expectancy  3.584e+07  1.245e+06   28.79   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 6.7e+07 on 54 degrees of freedom
##   (1 observation deleted due to missingness)
## Multiple R-squared:  0.9388, Adjusted R-squared:  0.9377 
## F-statistic: 828.6 on 1 and 54 DF,  p-value: < 2.2e-16
summary(fit4)
## 
## Call:
## lm(formula = gdp ~ life_expectancy, data = IndiaGDPLE)
## 
## Residuals:
##        Min         1Q     Median         3Q        Max 
## -1.469e+11 -1.179e+11 -3.708e+10  8.482e+10  4.181e+11 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)     -1.371e+12  1.631e+11  -8.405 3.96e-11 ***
## life_expectancy  3.033e+10  2.912e+09  10.417 3.99e-14 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.438e+11 on 50 degrees of freedom
##   (5 observations deleted due to missingness)
## Multiple R-squared:  0.6846, Adjusted R-squared:  0.6783 
## F-statistic: 108.5 on 1 and 50 DF,  p-value: 3.993e-14

Both have p-values<0.05, so they are both statistically significant predictors of life expectancy.

tidy(fit3)
## # A tibble: 2 × 5
##   term                estimate std.error statistic  p.value
##   <chr>                  <dbl>     <dbl>     <dbl>    <dbl>
## 1 (Intercept)     -1175883500. 70781322.     -16.6 7.02e-23
## 2 life_expectancy    35843559.  1245180.      28.8 1.93e-34
tidy(fit4)
## # A tibble: 2 × 5
##   term            estimate     std.error statistic  p.value
##   <chr>              <dbl>         <dbl>     <dbl>    <dbl>
## 1 (Intercept)     -1.37e12 163097807766.     -8.40 3.96e-11
## 2 life_expectancy  3.03e10   2911602899.     10.4  3.99e-14