30 minutes Worked on hemocytometer usage. I put 73 dots on a hemocytometer grid print-out.
40 minutes Worked on a GRE microbial temperature problem
30 minutes, Worked on a dilution questions again. (did not get into the plating question).
To explain standard deviation, I drew a chart on the board, with average as the horizontal line, and dots above or below the line. Squares are then drawn to explains the variance and standard deviations.
I was not clear on the interpret of standard deviation. One stddev should be 68%, two stddev should be 95%.
The concepts that students found difficult are:
1. How the volume of hemocytometer square is decided.
Some students did
2. unit conversion from ul^-1 to ml^-1 during concentration calculation. When the unit is in the denominator, it seems to throw some student off balance.
3. Standard deviation
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