Valley Corporation purchased a new piece of equipment on June 1, 2015. The cost of this machine was $325,000. The company estimated that the machine would have a salvage value of $25,000 at the end of its service life. Its life is estimated at four years, and its working hours are estimated at 50,000 hours. The year end is December 31.

Compute the depreciation expense under the following methods in an Excel spreadsheet. Each of the following should be considered unrelated:

Straight-line depreciation for 2015

Units of production method for 2015, assuming that machine usage was 13,000 hours

Sum-of-the-years