To merge two or several arrays of real use the following construct.

set a to {a1, a2, a3} as array of real

This concatenates the three arrays of real into one.

You can mix arrays of real and numbers.

set a to {0, 1 / 4} as array of real
set b to {1 / 2, 3 / 4} as array of real
set c to {a, b, 1} as array of real
c as list of real
  --  {0.0, 0.25, 0.5, 0.75, 1.0}