You have lost the sensation, but not movement, in one of your hands due to a problem with your spinal cord neurons. based upon these symptoms, what type of neuron was most likely affected

A sensory neuron.

Explanation:

The nervous system can be divided in two systems: the central nervous system and the peripheral nervous system. The central nervous system (CNS) is composed by the brain and the spinal cord. The peripheral nervous system (PNS) consists of the nerves and ganglia. Neurons are specialized cells that form the basic functional unit of the nervous system. There are three types of neurons: sensory, motor and interneurons. The sensory neurons are in charge of bringing signals into the CNS, and the motor neurons are in charge of carrying signals out of the CNS. The interneurons act as intermediaries, passing information between two neurons.  

As the name implies, sensory neurons are activated by the senses, for example: sound, visible light, physical contact (heat and cold), chemical signals (smell and taste). The loss of sensation in one hand would be the result of a damaged sensory neuron.  

it also supports my hypothesis. if you rest first you can squeeze the clothespin more times. from the data i collected the average of the eight people concluded exercise makes your muscles more fatigued and less able to squeeze the clothespin compared to resting before squeezing.