U.S. Bureau of Economic Analysis
Millions of Units, Seasonally Adjusted Annual Rate
Total vehicle sales indicates the number of drivers, number of vehicles, vehicle supply and demand, and overall economic strength.
The data shows autocorrection and a non-normal distribution. The data should be differenced. While the Order Norm transformation, provides the best normality, the Exponenetal variable will also perform well.
Data is able to be distributed by time but not by geography. The roll up method used is Sum.
Auto & Light Truck Vehicle Sales - Seas Adj
Auto Correction Function
Auto Correlation Function After Differencing
Partial Auto Correlation Function
Seasonal and Trend Decompostion
Data shows autocorrectation indicating a need for differencing
The ACF indicates 1 order differencing is appropriate.
Following first order differencing, no further differencing is required based on the differenced ACF at lag one of -0.35
The Kwiatkowski-Phillips-Schmidt-Shin (KPSS) test, KPSS Trend = 0.60 p-value = 0.01 indicates that the data is not stationary.
The Shapiro-Wilk test returned W = 0.88 with a p-value =0.00 indicating the data does not follow a normal distribution.
A skewness score of -0.97 indicates the data are moderately skewed.
Hartigan's dip test score of 0.04 with a p-value of 0.36 inidcates the data is unimodal
Statistics (Pearson P/ df, lower => more normal)
U.S. Bureau of Economic Analysis, Total Vehicle Sales [TOTALSA], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/TOTALSA, December 16, 2019.