Question

b. now that you have seen some of the assumptions and limitations associated with experimentation, try your hand at analyzing experimental data. remember that you must be objective, regardless of what you are trying to prove.

a scientist wished to determine if a new type of antibiotic, called antibiotic f, was effective against a particular type of microorganism that caused pneumonia. to test the hypothesis, the scientist found 100 volunteers in a large hospital, all suffering from the same type of pneumonia. the scientist gave 50 of the volunteers the new antibiotic for 10 days. the other 50 volunteers were given a sugar pill for 10 days. the sugar pill is called a placebo.

the scientist measured the effectiveness of the antibiotic by measuring each volunteer’s temperature. higher than normal body temperature indicated the presence of the disease-causing microorganisms. when a volunteer’s temperature remained normal (37°c) for three days, he or she was considered free of the disease-causing microorganism.

1. what was the scientist’s hypothesis? _______________

1. identify the control group. _______________

1. identify the experimental group. _______________

(graphs: four graphs labeled i, ii, iii, iv with key: received antibiotic f, received placebo. axes: time (days) 2-10, average of daily temperatures (°c) 37-40)

1. which graph indicates that the antibiotic was not effective against the disease-causing microorganism? explain your answer. _______________

1. which graph supports the scientist’s original hypothesis? explain your answer. _______________

1. can you think of any other observations or comparisons the scientist might have made in this experiment? _______________

1. why do you think the scientist gave 50 of the volunteers a placebo? _______________

Explanation:

1. Hypothesis is the testable claim about antibiotic F's effectiveness.
2. Control group lacks the treatment (antibiotic) to compare results.
3. Experimental group receives the treatment (antibiotic) being tested.
4. Antibiotic ineffective if experimental group's temp doesn't normalize.
5. Hypothesis supported if experimental group's temp normalizes vs placebo.
6. Additional observations could measure other disease indicators.
7. Placebo controls for psychological effects of treatment perception.

Answer:

1. Antibiotic F is effective against the particular type of microorganism that causes pneumonia.
2. The 50 volunteers given the sugar pill (placebo) for 10 days.
3. The 50 volunteers given antibiotic F for 10 days.
4. Graph I (assuming both groups show persistently elevated temperatures without returning to 37°C, indicating no effect of the antibiotic).
5. Graph III (assuming the experimental group's average temperature decreases to 37°C while the placebo group remains elevated, supporting effectiveness).
6. The scientist might have observed other symptoms (e.g., cough, fatigue), measured microorganism levels in blood/urine, or recorded recovery time.
7. To control for the placebo effect, ensuring any observed improvement is due to the antibiotic rather than psychological factors.