What do we call the “rd” in “3ʳᵈ” and the “th” in “9ᵗʰ”? @WS2 In speech, very nearly always In writing, much less so I think what may be going on is that one just assumes that “June 1” is pronounced “June First”, or “4 July” as “the Fourth of July”
science - abbreviations for standard deviation when used as an . . . "Standard deviation" is often abbreviated as "Std Dev" or "SD" in statistics, standard deviation providing an indication of how far data deviate from the mean Examples: So the SD(X) is the √Var(X) So the Std Dev of X is the sqrt of the Var of X You can also use a small sigma (i e , σ), but gauge your audience