Doctors suspect a strain of bacteria found in the hospital is becoming resistant to antibiotics. They put
various concentrations of antibiotic in petri dishes and
add some of the bacteria to allow it to grow. The
bacteria grow into groups in the dish called colonies.
After some time, the doctors return to the petri dishes
and count the number of colonies for the different
amounts of antibiotic. The data is plotted with a best fit
line.
The correlation coefficient was r=-0.83.
What does the sign of the correlation coefficient
r= -0.83) tell you about the relationship between the
number of bacteria colonies and the concentration of
antibiotic in the dish?