Figure 4.

The treatment effect was determined as the difference of log transformed count between each treatment and the paired sonicated control that removed any variation between runs. A negative number indicates fewer organisms and a positive number indicates a higher plate count. Standard error bars are included. All of the E. coli groups are centered around 0, which means there were no differences. There were more organisms in the S. epidermidis groups treated with shock waves, with the group treated with 2000 pulses in the horizontal position being significantly higher (P = 0.0445).