1. Statistical Experiments

3. Zener Cards Experiment
In the clip, Dr. Peter Venkman (Bill Murray) is conducting an experiment:
What was the experiment testing for?
The effect of negative reinforcement on ESP (Extra Sensory Perception)
What would Dr. Venkman have been recording?
How many/which ones the experimental unit got correct
What was the treatment or stimulus?
Negative reinforcement (the electric shock)
The effect of negative reinforcement on ESP (Extra Sensory Perception) 2. How many/which ones the experimental unit got correct
3. Negative reinforcement (the electric shock) 4. Yes correct by guessing 6. Have a class discussion on this. Is 20 enough? 50? Can we ever be 100% sure with this test?
7. No. Firstly, the negative reinforcement was given when the subject got the answer correct. Secondly, the “control” who didn’t get shocked should have been tested at a different time. Ethically, it is a terrible experiment!

4. Zener Cards Experiment
Is it possible for the subject to have just guessed the correct answer?
Yes
The experiment is repeated 80 times for each person. If there are 5 possible answers, how many out of 80 would you expect them to get right if they just guessed?
16 Correct by guessing
How many out of 80 would they need to get right to show evidence of Extra Sensory Perception?
Is 20 enough? 50? Can we ever be 100% sure with this test?
Is it a well designed experiment?
No.
Firstly, the negative reinforcement was given when the subject got the right answer
Secondly, the ‘control’ who didn’t get shocked should have been tested at a different time

5. Overall a terrible unethical experiment!!

6. This photo of a young Afghan girl Sharbat Gula has become an iconic image over the years since it featured on the cover of National Geographic magazine in The photograph was taken at the Nasir Bagh refugee camp in 1984 by photographer Steve McCurry. The girl was one of the students in an informal school within the refugee camp; McCurry, rarely given the opportunity to photograph Afghan women, seized the opportunity and captured her image. She was approximately 12 years old at the time.

7. Honesty Box Experiment
An experiment was carried out in a staff common room at Newcastle University in England. There was an ‘honesty box’ system in place to pay for tea/coffee use. Each week, an A5 poster was put above the box. One week it has a picture of flowers, the other it has a picture of a pair of eyes.
Handout: Newcastle Honest experiment BBC Article.docx. Read this first

8. Honesty Box Experiment
There were about 48 staff who used the common room, and the honesty box system has been in use for years, so users had no idea that an experiment was taking place.
Each week the research team recorded the total amount of money collected and the volume of milk consumed as this was considered to be the best index available of total drink consumption.
The team then calculated the ratio of money collected to the volume of milk consumed in each week. On average, people paid 2.76 as much for their drinks on the weeks when the poster featured pictures of eyes.

9. Honesty Box Experiment
What was being measured?
What was the ‘experiment’ here?

10. Controlled experimentation on scurvy
In 1747, while serving on the HMS Salisbury, surgeon James Lind carried out a controlled experiment to develop a cure for scurvy.
Scurvy was a problem for sailors. During Anson's circumnavigation of the world in 1740, he lost 1400 men out of an original crew of most of them allegedly from having contracted scurvy.
Unknown at the time, scurvy is a disease resulting from a deficiency of vitamin C. Symptoms are malaise and lethargy, spots on the skin, bleeding gums and mucous membranes.
This is described as the “first” controlled medical experiment. Key idea: Why was it important to come up with a scurvy cure?
A person with scurvy looks pale, feels depressed, and is partially immobilized.
As it advances, there can be open, pus-forming wounds, loss of teeth, jaundice, fever and death.

11. The effect of scurvy on skin. New England Journal of Medicine

12. Controlled experimentation on scurvy
Lind selected 12 men from the ship, all suffering from scurvy. Lind limited his subjects to men who "were as similar as I could have them“.
He divided them into six pairs, giving each pair different supplements to their basic diet for two weeks.
The treatments were all remedies that had been suggested previously:
A quart of cider every day.
Twenty five drops of elixir vitriol (sulphuric acid) three times a day upon an empty stomach.
One half-pint of seawater every day.
A mixture of garlic, mustard, and horseradish in a golf-ball sized lump, with barley water.
Two spoonful's of vinegar three times a day.
Two oranges and one lemon every day.
Lind was following a line of thought that acid could help cure scurvy, hence the reliance on acidic treatments.
The group taking the cider also showed a little improvement.

13. Source: http://www. clinist

14. Controlled experimentation on scurvy
The men who had been given citrus fruits recovered dramatically within a week. One of them returned to duty after 6 days and the other cared for the rest.
The others experienced some improvement, but nothing was comparable to the citrus fruits, which were proved to be substantially superior to the other treatments.
Questions for discussion
Why did Lind pick men who were “as similar as I could have them”?
To try to control for other factors
Why did he put them in pairs?
Having both respond the same gives more evidence than if one person did
What were his “experimental units”
The sailors

15. More questions for discussion
How was Lind controlling for other variables?
By keeping their standard rations the same (controlling their diet) and giving them the same treatment on top of this each day.
How could he tell if the treatment worked?
They got better – the effects of scurvy reduced, etc.
What would have been a good follow-up experiment to confirm his findings?
Having a “control group” of just standard rations vs a group with “Rations plus citrus fruits”. Perhaps having several treatment groups with different types or quantities of citrus fruits. Or a group that gets just the juice vs whole fruit.