Hi, and welcome!
This isn't quite a reproducible example, called a reprex because we don't have newvector. It's generally a good idea to include a reprex to attract more and better answers.
In this case, however, it's easy enough to replicate the situation.
## Annette Dobson (1990) "An Introduction to Generalized Linear Models".
## Page 9: Plant Weight Data.
newvector <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
## how long is newvector?
length(newvector)
#> [1] 10
## what is the second element of newvector?
newvector[2]
#> [1] 5.58
## what is the tenth (11-1) element?
newvector[10]
#> [1] 5.14
## what are the second to tenth elements of newvector?
newvector[2:10]
#> [1] 5.58 5.18 6.11 4.50 4.61 5.17 4.53 5.33 5.14
## assign the second to tenth elements of newvector to newvariable
newvariable <- newvector[2:11-1]
newvariable
#> [1] 4.17 5.58 5.18 6.11 4.50 4.61 5.17 4.53 5.33 5.14
## how long is newvariable?
length(newvariable)
#> [1] 10
## is it identical to newvector[1:10]?
newvariable == newvector[1:10]
#> [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
## what is in newvector[2:(11-1)]
newvector[2:(11-1)]
#> [1] 5.58 5.18 6.11 4.50 4.61 5.17 4.53 5.33 5.14
## how long is it?
length(newvector[2:(11-1)])
#> [1] 9
Created on 2020-01-12 by the reprex package (v0.3.0)