Applescript if statement : greater than and lower than

Can I run an script if a variable is between 4 and 6 characters only ?

e.g

set serialNumber to ""
set theLength to (get length of (serialNumber as text))
if theLength is equal to 1 then
    set serialNumber to "No Serial"
else if theLength > 4 and < 6 then
    ##do this
else if theLength is greater than 6 then
    ## do nothing
end if

This is obviously not working : else if theLength > 4 and < 6 then


Change:

else if theLength > 4 and < 6 then

To:

else if theLength > 4 and theLength < 6 then

Or, since you asked "Can I run a script if a variable is between 4 and 6 characters only?", which is equal to 5, you can also use:

else if theLength = 5 then

In place of:

else if theLength > 4 and theLength < 6 then

However, if testing between two numbers that are (one or) more then one, just use the variable twice in the test as shown above.