想象一个情况:我们有三个矿山的历史记录(20 年)。白银的存在是否会增加明年发现黄金的可能性?如何测试这样的问题?
这是示例数据:
mine_A <- c("silver","rock","gold","gold","gold","gold","gold",
"rock","rock","rock","rock","silver","rock","rock",
"rock","rock","rock","silver","rock","rock")
mine_B <- c("rock","rock","rock","rock","silver","rock","rock",
"silver","gold","gold","gold","gold","gold","rock",
"silver","rock","rock","rock","rock","rock")
mine_C <- c("rock","rock","silver","rock","rock","rock","rock",
"rock","silver","rock","rock","rock","rock","silver",
"gold","gold","gold","gold","gold","gold")
time <- seq(from = 1, to = 20, by = 1)