[SciPy-User] why does scipy.stats.t.ppf return negative values?

[pybokeh]

I am reviewing sample problems in my statistics book from college.  When I
look up the percentage point for t-distribution in the appendix of the
book, it lists positive values.  When I use say for example:
stats.t.ppf(0.025,15), it shows -2.131, whereas, my stat book shows 2.131.
I tried other parameters and I get same values as what my stat book shows,
but again the values it returns are negative.
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