销售割草机在北美地区显示季节性趋势与销售在6月和12月触及低峰值。虽然数字的变化没有维护稳定的加法或乘法模式增加,销售额稳步增长数字的一般趋势是专门为6月发现的。而欧洲数字几乎相同的大约5个月,然后下降,在1月达到最小,然后又急剧上升。行业数据为同一遵循相同的模式。拖拉机单位销售额不一致的兴衰和欧洲数量没有遵循一组模式的头3年即2008 – 2011年。和行业数字反映相同。
The sales of Lawn Mowers and Tractors and its industry sales and trends have 2 major components – the months and the sales figures for these months across a time period of 4 years. And so a simple linear regression would help us understand the relationship between the two.
Sales of Lawn Mowers in the North America region showed a seasonality trend with sales peaking during June and hitting a low in December. While the change in the numbers did not uphold a steady pattern of additive or multiplicative increases, the general trend of a steady increase in sales numbers were found specifically for the month of June. Whereas Europe numbers were almost same for about 5 months of the year and would then decline, reach the minimal in Jan and then sharply rise again. The industry numbers for the same followed an identical pattern. The tractor unit sales were inconsistent in their rise and decline and the Europe number did not follow a set pattern for the first 3 years i.e. 2008-2011. And the industry numbers mirrored the same.
To be able to plot the same, the data was stripped off its seasonality effect and de-trended. For the Mower and Tractor sales for North America, Europe, and consequently industry sales numbers, the adjusted S data was derived from adjusted sales numbers for the 4 years averaged for each month so as to calculate a seasonality trend for each of these months. The fitted ŷ is the summation of ŷ +adj s. The models were picked according to their statistic relevance by checking the Mean Absolute Percentage Error.