The Walking Man

I don't have a car and I don't like taking transit. Consequently, I get to most places on my own two feet. Recently, I obtained a pedometer and decided to check out just how many steps I take each day. I wrote down the numbers each day when I arrived at work, left work, and arrived home. Here's how they panned out:

Monday

• Arrival at work - 2667
• Departing work - 2926
• Arrival at home - 6099

Tuesday

• Arrival at work - 2258
• Departing work - 4882
• Arrival at home - 7755

Wednesday

• Arrival at work - 2620
• Departing work - 3406
• Arrival at home - 6484

Thursday

• Arrival at work - 3176
• Departing work - 4760
• Arrival at home - 9882

Now, I'm not surprised to see the numbers fluctuate at the time I depart work because some days I don't venture too far from my desk, other days I do a bit of walking around campus. Likewise, some days I walk straight home, other days I stop for a few errands.

What I don't understand is the variance in the number of steps when I arrive at work, especially Thursday's stat. I travel the exact same path to work every morning; how can there possibly be a 1,000 step margin for error?