Data Import

Sales Analysis

From the plot above, it suggests that sales are generally higher towards the end of the year and dip significantly at the beginning of the year. There also a general upward trend for sales - the total amount sold is approx. twice as much as 2013 in 2017.

Average Sales Analysis

Results suggests that sales in decemember is the highest. This is as expected since consumption should be higher during the Christmas holidays. To further confirm this, I will be condcuting an analysis on the average sales of each holiday season. The goal is to understand which public holiday has the highest average sales.

From the pie chart, it suggests that type A stores has the highest averages sales followed by type D and C.

Holiday and average sales

Plot confirms that type A stores has the highest sales, and average sales are higher during the following holiday type: transfer, bridge, additional

Average sales per day of week analysis

From the plot above, it suggests that sales are higher towards the end of the week. People consume more on friday, saturday and sundays in general.

Time Series analysis and forecast

Stationary testing

Dicky Fuller Test suggests that our data is stationary. However, i suspect that seasonality is evident in the data as average sales are higher in December and lower in January.

As per autocorrelation, the data is less autocorrelated with more lags.

First Differencing to remove seasonality

Orders of the ARMA model

Plots

Mean squared Error