预测在邮电计划上的应用,大致有两种方法。第一、通过社会调查,进行市场预测;第二、运用产品的历史资料,找出“倾向变动线”,进行统计预测。下面先谈谈统计预测: 一、对于近年来增长比例比较大、发展趋势比较明显的业务如电报、长话,除调查社会因素外,采用“直线式最小平方法”。其公式为:y=a+bx Predict the application in the postal plan, there are basically two ways. First, conduct market surveys through social surveys; second, use the historical data of products to find the “trend-changing line” and make statistical forecasts. First of all, talk about the statistical forecast: First, the proportion of larger growth in recent years, the development trend of more obvious business such as telegraphy, long distance, in addition to investigating social factors, the use of “linear least square method.” The formula is: y = a + bx