1 Cargar los paquetes necesarios

2 Cargar base de datos

df <- read.csv("C:/Users/chio0/Desktop/tito/Aplicaciones/Documents/7 semestre/P. Antonio/tema que falte/Sample - Superstore.csv")
head(df)
##   Row.ID       Order.ID Order.Date  Ship.Date      Ship.Mode Customer.ID
## 1      1 CA-2016-152156  11/8/2016 11/11/2016   Second Class    CG-12520
## 2      2 CA-2016-152156  11/8/2016 11/11/2016   Second Class    CG-12520
## 3      3 CA-2016-138688  6/12/2016  6/16/2016   Second Class    DV-13045
## 4      4 US-2015-108966 10/11/2015 10/18/2015 Standard Class    SO-20335
## 5      5 US-2015-108966 10/11/2015 10/18/2015 Standard Class    SO-20335
## 6      6 CA-2014-115812   6/9/2014  6/14/2014 Standard Class    BH-11710
##     Customer.Name   Segment       Country            City      State
## 1     Claire Gute  Consumer United States       Henderson   Kentucky
## 2     Claire Gute  Consumer United States       Henderson   Kentucky
## 3 Darrin Van Huff Corporate United States     Los Angeles California
## 4  Sean O'Donnell  Consumer United States Fort Lauderdale    Florida
## 5  Sean O'Donnell  Consumer United States Fort Lauderdale    Florida
## 6 Brosina Hoffman  Consumer United States     Los Angeles California
##   Postal.Code Region      Product.ID        Category Sub.Category
## 1       42420  South FUR-BO-10001798       Furniture    Bookcases
## 2       42420  South FUR-CH-10000454       Furniture       Chairs
## 3       90036   West OFF-LA-10000240 Office Supplies       Labels
## 4       33311  South FUR-TA-10000577       Furniture       Tables
## 5       33311  South OFF-ST-10000760 Office Supplies      Storage
## 6       90032   West FUR-FU-10001487       Furniture  Furnishings
##                                                       Product.Name    Sales
## 1                                Bush Somerset Collection Bookcase 261.9600
## 2      Hon Deluxe Fabric Upholstered Stacking Chairs, Rounded Back 731.9400
## 3        Self-Adhesive Address Labels for Typewriters by Universal  14.6200
## 4                    Bretford CR4500 Series Slim Rectangular Table 957.5775
## 5                                   Eldon Fold 'N Roll Cart System  22.3680
## 6 Eldon Expressions Wood and Plastic Desk Accessories, Cherry Wood  48.8600
##   Quantity Discount    Profit
## 1        2     0.00   41.9136
## 2        3     0.00  219.5820
## 3        2     0.00    6.8714
## 4        5     0.45 -383.0310
## 5        2     0.20    2.5164
## 6        7     0.00   14.1694

3 Modificacion de columnas

df_mod <- df %>% # Llamar a la base de datos 
  filter(State == "Michigan") %>% # Este es el paso
  select(Order.Date, Sales) %>% # Llamar a la base de datos 
  mutate(Order.Date = mdy(Order.Date)) %>% # Seleccionamos dos columnas Order.date y sales 
  mutate(Fecha = floor_date(Order.Date, unit= "month")) %>% # Regresar al inicio de mes
  group_by(Fecha) %>% # Agrupar por mes
  summarise(Ventas = sum(Sales)) %>% # Hacer la suma
  mutate(Mes = month(Fecha))  # Extraer solo el mes de la fecha

head(df_mod)
## # A tibble: 6 × 3
##   Fecha      Ventas   Mes
##   <date>      <dbl> <dbl>
## 1 2014-01-01  949.      1
## 2 2014-03-01   22.4     3
## 3 2014-04-01  855.      4
## 4 2014-05-01  104.      5
## 5 2014-06-01  930.      6
## 6 2014-08-01 1129.      8

4 Visualizacion

df_mod %>%
  ggplot(., aes(x=Mes, y=Ventas)) +
  geom_point() +
  geom_line() +
  geom_smooth(method = "lm", formula = "y ~ x")

# 5 Grafica de caja y bigotes

#Esta grafica me sirve para encontrar valres atipicos
df_mod %>%
  ggplot(., aes(x=Ventas)) +
  geom_boxplot()

# 6 Revisar si la variable y tiene una distribucion aprox normal

df_mod %>%
  ggplot(., aes(x=Ventas)) +
  geom_histogram(bins = 30, aes(y=..density..))+
  geom_density()
## Warning: The dot-dot notation (`..density..`) was deprecated in ggplot2 3.4.0.
## ℹ Please use `after_stat(density)` instead.
## This warning is displayed once every 8 hours.
## Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
## generated.

# 7 Analisis de correlacion

#Calculamos coeficientes de correlacion de Person, con mes como x 
with(df_mod, cor.test(Mes, Ventas))
## 
##  Pearson's product-moment correlation
## 
## data:  Mes and Ventas
## t = 0.6024, df = 38, p-value = 0.5505
## alternative hypothesis: true correlation is not equal to 0
## 95 percent confidence interval:
##  -0.2209448  0.3967476
## sample estimates:
##        cor 
## 0.09725846

8 Modelo de regresion

modelo_lineal <-lm(Ventas ~ Mes, data = df_mod)
stargazer(modelo_lineal, type = "text")
## 
## ===============================================
##                         Dependent variable:    
##                     ---------------------------
##                               Ventas           
## -----------------------------------------------
## Mes                           77.990           
##                              (129.467)         
##                                                
## Constant                     1,347.159         
##                             (1,019.216)        
##                                                
## -----------------------------------------------
## Observations                    40             
## R2                             0.009           
## Adjusted R2                   -0.017           
## Residual Std. Error     2,652.567 (df = 38)    
## F Statistic             0.363 (df = 1; 38)     
## ===============================================
## Note:               *p<0.1; **p<0.05; ***p<0.01

9 Coeficientes de modelo

#Obtener los coeficientes del modelo, es decir a y b 
coeficientes <- coef(modelo_lineal)
intercepto <- coeficientes["(Intercept)"]
pendiente <- coeficientes["Mes"]


#Crear el texto de la ecuacion 
ecuacion <-paste0("y = ", round(intercepto, 2),
                  " + ",
                  round(pendiente, 2), "x")
ecuacion
## [1] "y = 1347.16 + 77.99x"

10 Prediccion

#Extender la sere temporal para 6 meses 
df_futuro <- data.frame(Fecha = seq.Date(from = max(df_mod$Fecha) + months(1),
                            by = "month",
                            length.out = 6),
           Mes = seq(from = 49, to = 54, by = 1))
#generar las predicciones para 6 meses con intervalos de confianza
predicciones <- predict(modelo_lineal,
                        newdata = df_futuro,
                        interval = "confidence")
predicciones
##        fit       lwr      upr
## 1 5168.688 -5826.125 16163.50
## 2 5246.678 -6009.462 16502.82
## 3 5324.669 -6192.834 16842.17
## 4 5402.659 -6376.238 17181.56
## 5 5480.650 -6559.672 17520.97
## 6 5558.640 -6743.135 17860.41

11 Juntar datos

# Covertir predicciones a un data frame 
df_predicciones <- as.data.frame(predicciones)
colnames(df_predicciones) <- c("Ventas" , "Bajo", "Alto")
# Unir las predicciones y los intervalos de confianza con las fechas 
df_futuro <- cbind(df_futuro, df_predicciones) #cbind une por columnas 

#unir con la base de datos original 
df_total <- bind_rows(df_mod, df_futuro)
tail(df_total, 7)
## # A tibble: 7 × 5
##   Fecha      Ventas   Mes   Bajo   Alto
##   <date>      <dbl> <dbl>  <dbl>  <dbl>
## 1 2017-12-01  4040.    12    NA     NA 
## 2 2018-01-01  5169.    49 -5826. 16164.
## 3 2018-02-01  5247.    50 -6009. 16503.
## 4 2018-03-01  5325.    51 -6193. 16842.
## 5 2018-04-01  5403.    52 -6376. 17182.
## 6 2018-05-01  5481.    53 -6560. 17521.
## 7 2018-06-01  5559.    54 -6743. 17860.

#12 Grafica con valores pasados

#Grafica con variable pasados y prediccion
df_total %>%
  ggplot(., aes(x = Fecha, y = Ventas)) +
  geom_point(data = df_mod) +
  geom_line(data = df_mod) +
  geom_smooth(method = "lm", formula = y ~ x, color = "blue", data = df_mod) +
  geom_ribbon(data = df_futuro, aes(ymin = Bajo, ymax = Alto),
              fill = "lightblue") +
  geom_point(data = df_futuro, aes(y = Ventas), color = "red")+
  geom_line(data = df_futuro, aes(y = Ventas, color = "red",
                                  linetype = "dashed"))