# Physics 3333 / CFB 3333 Homework 3 - Induction and Abduction

HINT: You may find it especially useful to read through Prof. Fisher's notes on types of arguments.

## Part 1. Induction.

Imagine that Dr. Wakemeadow is interested in the safety of a new vaccine. He gets a local pediatrician to select 12 infants who had been brought in to her office for treatment of various conditions. With parental permission, the pediatrician administers the vaccine to the 12 infants. Over the following 3 months, 58% of those infants were brought back to the pediatrician with health complaints, which is higher than the 42% average rate for all children that age to be taken to the doctor with health complaints. On this basis, Dr. Wakemeadow concludes that a majority of all infants who take this vaccine would experience health problems in the next three months.

Q2.1. What type of argument is Dr. Wakemeadow using? Explain your answer, noting what he is using as a sample, what target he is attempting to generalize to, and what trait he is generalizing from the sample to the target.
Q2.2. Comment on the sample-size used in this argument. Is there much risk that the increased percentage might just be a random fluke? How could Dr. Wakemeadow improve the experiment to address this worry?
Q2.3. Comment upon whether or not this sample is appropriately representative. Can you think of a better way to select a sample?

## Part 2. Abduction.

Andre is hiking in the wilderness, and he notices some depressions in wet sand, evenly spaced about three feet apart. The depressions are larger than his feet; they seem to have fuzzy rounded edges; and they and have texture in them that could be thick fur. Andre considers three potential explanations.

H1. An ordinary hiker walked through the sand leaving behind bootprints.
H2. Bigfoot (a big undiscovered ape) walked through the sand leaving behind hairy footprints.
H3. A hiker with a bunch of thick mud and grass stuck to his shoes walked through the sand.

Q3.1. Which of these hypotheses would the Prediction Principle tell you to favor over the other(s)? Why?
Q3.2. Which of these hypotheses would Ockham's Razor tell you to favor over the other(s)? Why?
Q3.3. Are there other hypotheses Andre should consider?
Q3.4. Are there other observations that Andre could look for to help decide which hypothesis is best?

## Part 3. Venn Diagrams

Part A.

Part B.
Also - draw a Venn diagram for A OR B => C.