Answer is seen below
Explanation: Stimulus frequency refers to the rate that stimulating voltage pulses are applied to an isolated whole skeletal muscle.
When a stimulus frequency is at the lowest ( let's say 50stimuli/second) the force will be at its lowest level out of all of the experiments. As the stimulus frequency was increased to 130 stimuli/second the force increased slightly but fused tetanus( tetanus refers to a sustained muscle tension due to very frequent stimuli) developed at the higher frequency. When the stimulus frequency was increased to the amounts of 146-150 stimuli/second, a maximum tetanic tension occurred, where no further increases in force occur from additional stimulus frequency.
By increasing the stimulus frequency if it resulted in increasing the muscle tension generated by each successive force and it had limit that was eventually reached. Then the results equaled to your prediction.