Hello,
I have a table with soil infiltration rates in minutes per cm and then converted to cm per hour (60/number of minutes). When I calculate the average of both columns, I get diferent measurements.
For example:
In min /cm: 300, 6.768, 1.712 average: 102.82
In cm / hour: 0.2, 8.86, 35.04 average: 14.70
But 102.82 min/cm does not equal 14.70 cm/hour.
Ive spend hours looking for my mystake but can´t find it, please help.
I don´t know if this kind of question is apropiate here. If not please point me to an apropiate forum.
Errata.- I wrote soil infiltration rates, but the correct term is soil water infiltration rates.
May be due to the fractions. Additionally, try to delete the outlier data. It is a fluctuated data with very high SD. Take more measures and look for the true average.
Infiltration rate = depth / time ( in your case measured in cm/min, but may also be cm/h, mm/h). A value reported in min/cm is not an infiltration rate, but its reverse.
Example: the infiltration rate was 1.0 cm/300 min = 0.0033 cm/min. This value may be also reported as 0.0033 cm/min x 60 min/h = 0.2 cm/h.
All values reported in cm/h are 60 times higher than the values reported in cm/min.
To clarify:
I used a single ring infiltrometer, my value of min/cm indicates the amount of minutes it took for a cm to infiltrate. Tis value is then converted to cm/hr.
So, after converting my column to cm / hr, I calculated the mean for it, but also calculated the mean of my original observations (min / cm). I expected both values to be the same, not the same number but conversible to each other, only to find they don´t. Hence my confusion.
Thanks for your answers.
Camilo
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