Simple Linear Regression

Weight against calories consumed

library(e1071)
## Warning: package 'e1071' was built under R version 3.5.1
Weight_Calories <- read.csv("E:\\Data Science\\data science\\assignments\\Simple Linear Regression\\calories_consumed.csv")

colnames(Weight_Calories) <-c("WeightInGrams", "Calories")
attach(Weight_Calories)
dim(Weight_Calories)
## [1] 14  2
#First Moment Busisness Decision
summary(Weight_Calories)
##  WeightInGrams       Calories   
##  Min.   :  62.0   Min.   :1400  
##  1st Qu.: 114.5   1st Qu.:1728  
##  Median : 200.0   Median :2250  
##  Mean   : 357.7   Mean   :2341  
##  3rd Qu.: 537.5   3rd Qu.:2775  
##  Max.   :1100.0   Max.   :3900
#Second Moment Busisness Decision
var(WeightInGrams)
## [1] 111350.7
var(Calories)
## [1] 565668.7
sd(WeightInGrams)
## [1] 333.6925
sd(Calories)
## [1] 752.1095
#Thrid Moment Busisness Decision
skewness(WeightInGrams)
## [1] 0.9994639
skewness(Calories)
## [1] 0.5212708
#Fourth Moment Busisness Decision
kurtosis(WeightInGrams)
## [1] -0.506441
kurtosis(Calories)
## [1] -0.9277095
plot(Calories, WeightInGrams, col = "Blue")

# Correlation coefficient for Weight and calories
cor(Calories, WeightInGrams)
## [1] 0.946991
slr <- lm(WeightInGrams~Calories)

confint(slr, level = 0.95)
##                    2.5 %       97.5 %
## (Intercept) -845.4266546 -406.0780569
## Calories       0.3305064    0.5098069
predict(slr, interval = "predict")
## Warning in predict.lm(slr, interval = "predict"): predictions on current data refer to _future_ responses
##            fit        lwr       upr
## 1     4.482599 -258.20569  267.1709
## 2   340.607908   88.93791  592.2779
## 3   802.780209  533.81393 1071.7465
## 4   298.592245   46.63271  550.5518
## 5   424.639236  172.59086  676.6876
## 6    46.498263 -213.75953  306.7561
## 7   -37.533065 -302.93258  227.8664
## 8   172.545254  -82.18110  427.2716
## 9   550.686227  295.69632  805.6761
## 10 1012.858527  724.99432 1300.7227
## 11   75.909227 -182.81852  334.6370
## 12  172.545254  -82.18110  427.2716
## 13  508.670563  254.97398  762.3671
## 14  634.717554  376.22600  893.2091
summary(slr)
## 
## Call:
## lm(formula = WeightInGrams ~ Calories)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -158.67 -107.56   36.70   81.68  165.53 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept) -625.75236  100.82293  -6.206 4.54e-05 ***
## Calories       0.42016    0.04115  10.211 2.86e-07 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 111.6 on 12 degrees of freedom
## Multiple R-squared:  0.8968, Adjusted R-squared:  0.8882 
## F-statistic: 104.3 on 1 and 12 DF,  p-value: 2.856e-07
# R-squared value for the above model is 0.8968.
# The R-sqaured value is higher -  Weight and Calories model is good.