Flexor+and+Extensor+Muscles

Question: Which muscles are stronger, Flexor or Extensor Muscles?

Hypothesis: I thought that I might get at least 20 in both but i didn't Why because I didn't try hard enough.

Procedure: Get into groups Have one person stand up straight with his / her back against a wall. Have that person hold the weights in his / her dominant hand In a "curling" motion, have the student raise and lower the weights until his / her arms get tired. Repeat steps 2-4 for each member of the group. Record the data for each member of the group. Have the first person stand as straight as possible near a wall. Have the student hold the weights with his / her dominant arm bent near the ear. In a motion that mimics throwing, have the student extend the weights above his / her head until the dominant arm gets tired. Repeat steps 7-9 for each member of the group. Record the data for each member of the group.

Data:

Flex Extensor
 * Boy 54 || 32 ||
 * Girl 30 || 16 ||
 * Girl 16 || 2 ||
 * Girl 15 || 5 ||
 * Girl 11 || 1 ||

Conclusion: I thought thata I might get 20 at least but I didn't in both.