I want to run a t-test that the population mean is equal to a specified value given by a scalar. For example, the sample of the population is given by the variable "mpg" and the scalar has the name "alpha" and is equal to 23.

However, using the syntax
Code:
ttest mpg == alpha
yields "variable alpha not found".

Using the syntax
Code:
ttest mpg == `alpha'
yields "invalid syntax"

While using the syntax
Code:
ttest mpg == 23
works.

How can I make "ttest" read the numerical value of the scalar "alpha"?