Cyclic frequency of unknown weight

[AdnamaLeigh]

When an unknown weight W was suspended from a spring with an unknown force constant k, it reached its equilibrium position and the spring was stretched 14.2cm because of the weight W. Then the weight W was pulled further down to a position 16cm (1.8cm below its equilibrium position) and released, which caused an oscillation in the spring. Calculate the cyclic frequency of the resulting motion. Answer in Hz.

I set k=F/x:
k=9.8m/.018 = 544.44m

I used T=2π√(m/k) to solve for the period:
T=2π√(m/544.44m) = .269s The mass canceled out

I did 1/T for frequency:
1/.269 = 3.714Hz

The answer is wrong. I think it might have something to do with the 14.2cm information but I don't know how to incorporate it in the problem.

 

[Tide]

You need to use the 14.2 cm to calculate the spring constant.