helmet <-
structure(list(lunch = c(50L, 11L, 2L, 19L, 26L, 73L, 81L, 51L, 
11L, 2L, 19L, 25L), helmet = c(22.100000000000001, 35.899999999999999, 
57.899999999999999, 22.199999999999999, 42.399999999999999, 5.7999999999999998, 
3.6000000000000001, 21.399999999999999, 55.200000000000003, 33.299999999999997, 
32.399999999999999, 38.399999999999999)), row.names = c(NA, -12L
), class = c("tbl_df", "tbl", "data.frame"))