a <- read.csv("C:\\Users\\Harisha\\Desktop\\Datascience Assignments\\Basic stats 1\\Computer_Data.csv")
attach(a)
View(a)
summary(a)
## X price speed hd
## Min. : 1 Min. : 949 Min. : 25.00 Min. : 80.0
## 1st Qu.:1566 1st Qu.:1794 1st Qu.: 33.00 1st Qu.: 214.0
## Median :3130 Median :2144 Median : 50.00 Median : 340.0
## Mean :3130 Mean :2220 Mean : 52.01 Mean : 416.6
## 3rd Qu.:4694 3rd Qu.:2595 3rd Qu.: 66.00 3rd Qu.: 528.0
## Max. :6259 Max. :5399 Max. :100.00 Max. :2100.0
## ram screen cd multi premium
## Min. : 2.000 Min. :14.00 no :3351 no :5386 no : 612
## 1st Qu.: 4.000 1st Qu.:14.00 yes:2908 yes: 873 yes:5647
## Median : 8.000 Median :14.00
## Mean : 8.287 Mean :14.61
## 3rd Qu.: 8.000 3rd Qu.:15.00
## Max. :32.000 Max. :17.00
## ads trend
## Min. : 39.0 Min. : 1.00
## 1st Qu.:162.5 1st Qu.:10.00
## Median :246.0 Median :16.00
## Mean :221.3 Mean :15.93
## 3rd Qu.:275.0 3rd Qu.:21.50
## Max. :339.0 Max. :35.00
var(price)
## [1] 337333.2
var(speed)
## [1] 447.6498
var(hd)
## [1] 66847.3
var(ram)
## [1] 31.70928
var(screen)
## [1] 0.8192336
var(ads)
## [1] 5600.32
sd(price)
## [1] 580.804
sd(speed)
## [1] 21.15774
sd(hd)
## [1] 258.5484
sd(ram)
## [1] 5.631099
sd(screen)
## [1] 0.9051152
sd(ads)
## [1] 74.83528
library(e1071)
skewness(price)
## [1] 0.7113836
skewness(speed)
## [1] 0.6566931
skewness(hd)
## [1] 1.377359
skewness(ram)
## [1] 1.385538
skewness(screen)
## [1] 1.633225
skewness(ads)
## [1] -0.5530629
kurtosis(price)
## [1] 0.7276838
kurtosis(speed)
## [1] -0.2770616
kurtosis(hd)
## [1] 2.447798
kurtosis(ram)
## [1] 1.458699
kurtosis(screen)
## [1] 1.847838
kurtosis(ads)
## [1] -0.5411566
barplot(price)
barplot(speed)
barplot(hd)
barplot(ram)
barplot(screen)
barplot(ads)
hist(price)
hist(speed)
hist(hd)
hist(ram)
hist(screen)
hist(ads)
boxplot(price)
boxplot(speed)
boxplot(hd)
boxplot(ram)
boxplot(screen)
boxplot(ads)
plot(a)
cor(a [,1:6])
## X price speed hd ram screen
## X 1.0000000 -0.1999235 0.3885662 0.5554922 0.2653759 0.1846995
## price -0.1999235 1.0000000 0.3009765 0.4302578 0.6227482 0.2960415
## speed 0.3885662 0.3009765 1.0000000 0.3723041 0.2347605 0.1890741
## hd 0.5554922 0.4302578 0.3723041 1.0000000 0.7777263 0.2328015
## ram 0.2653759 0.6227482 0.2347605 0.7777263 1.0000000 0.2089537
## screen 0.1846995 0.2960415 0.1890741 0.2328015 0.2089537 1.0000000
basic <- lm(price~speed+hd+ram+screen+ads)
summary(basic)
##
## Call:
## lm(formula = price ~ speed + hd + ram + screen + ads)
##
## Residuals:
## Min 1Q Median 3Q Max
## -907.35 -281.57 -71.97 201.70 2472.20
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) -405.73236 88.39492 -4.59 4.52e-06 ***
## speed 5.75103 0.27172 21.17 < 2e-16 ***
## hd -0.40739 0.03522 -11.56 < 2e-16 ***
## ram 73.59740 1.50119 49.03 < 2e-16 ***
## screen 107.19445 6.01382 17.82 < 2e-16 ***
## ads 1.44617 0.07502 19.28 < 2e-16 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 415.3 on 6253 degrees of freedom
## Multiple R-squared: 0.489, Adjusted R-squared: 0.4886
## F-statistic: 1197 on 5 and 6253 DF, p-value: < 2.2e-16
confint(basic, level=0.95)
## 2.5 % 97.5 %
## (Intercept) -579.0167674 -232.4479604
## speed 5.2183744 6.2836842
## hd -0.4764387 -0.3383346
## ram 70.6545500 76.5402537
## screen 95.4052921 118.9836100
## ads 1.2990954 1.5932383
confint(basic, level=0.90)
## 5 % 95 %
## (Intercept) -551.1506142 -260.314114
## speed 5.3040315 6.198027
## hd -0.4653343 -0.349439
## ram 71.1277949 76.067009
## screen 97.3011263 117.087776
## ads 1.3227462 1.569587
plot(basic)
