我有一个很棘手的问题。以下是我的数据: > structure(list(seconds = c(689, 689.25, 689.5, 689.75, 690, 690.25, 690.5, 690.75, 691, 691.25, 691.5, 691.75, 692, 692.25, 692.5 ), threat = c(NA, NA, NA, NA, NA, NA, 1L, 1L, 0L, 0L, 1L, NA, NA, 1L, 1L), bins = c(1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L