The aim of this research was to find out the effectiveness of guessing game to
improve speaking skill in teaching procedure at second grade students of SMK
Muhammadiyah 1 Purwokerto in academic year 2014/2015. This research used quasi
experimental research involving twenty two students of class XI AK 2 as
experimental class and twenty students of class XI AK 1 as control class. Guessing
game was applied in experimental class while control class was not given any special
treatment. Test was used to collect the data, namely pre-test and post-test. The test
focus on the language expression of present tense and imperative sentence. After data
was taken, it was analyzed using t-test formula. The result of t-test computation was
1.81, and the value of t-table at the level significance 0.05 with degree of freedom 40
was 1.68. Thus, the result of t-test computation was higher than the value of t-table
(1.81 > 1.68), and it means that the hypothesis was accepted. Therefore, it could be
concluded that guessing game was effective to improve speaking skill in teaching
procedure at second grade students of SMK Muhammadiyah 1 Purwokerto in
academic year 2014/2015.