Chapter 1
The Big Picture
Collective Intelligence
Theories
Evidence - provided by philosophers, scientists,
and mathematicians.
1. For humanity to maintain its large population and standard of
living, some pollution and destruction of the natural
environment is necessary. As a consequence, some species
will become extinct. What is an acceptable loss of species?
What is the intrinsic value of each species?
2. Why does carbon in the atmosphere lead to ocean
acidification and how does this affect plankton, oyster larvae,
etc.
3. How much money will be in an account in 5 years if you
invest 1000 at 2%, compounded monthly?
4. Is the Puget Sound healthy?
5. What is the best solution for poverty in America?
Statistical Process
1. Ask a specific question
2. Make a hypothesis
3. Design the research (study or experiment)
4. Collect data
5. Use graphs and statistics to explore the evidence (data)
6. Determine if the evidence supports the theory
7. Make an evidence-based decision
1. Ask a specific question
Difference between general (multiple dimensions) and specific
questions (one dimension)
Which of the following specific questions would help us answer
the general question. Rate each as mostly complete, partial insight,
useless.
General question: Is the Puget Sound healthy?
1. Is the mercury concentration in fish and shellfish
tissue high enough to cause health problems in the fish or humans?
Because consumption of contaminated fish and shellfish is the
primary route of human exposure to methylmercury, EPA is
expressing this water quality criterion as a fish and shellfish tissue
value rather than as a water column value.
2. What is the average number of cars transported daily
across the Sound by the Washington State Ferry System?
3.
What is the size of the herring stock in the Puget Sound?
(Herring is a keystone species with a unique position in the food
web of the Puget Sound being in the middle of the small organisms
on which they prey and being prey for larger organisms
General question: What is the best solution for poverty in
America?
1. Are there more discussions about poverty in the paper or
on TV news?
2. If education is the way out of poverty, is the proportion of
students from poverty in higher education the same as the
proportion of people in poverty?
3. For people who have transitioned from bottom 5th of
income to a higher level, which of the following made the biggest
contribution: social service program, education, dual income
earners, race, not being unemployed.
Go to In-class Activities – page 267
2. Make a hypothesis
Questions are asked because someone has to make a decision
(usually about $ or Health).
A theory is formulated then expressed as hypotheses. Each
hypothesis leads to a different decision.
H0: Null hypothesis – Assumed to be true – but cannot be
proven true
H1: Alternative hypothesis – Accepted if null is rejected –
often the desired outcome.
Question 1: Is the average tissue concentration more than 300 g
/kg? If it is, fishing will be prohibited.
Two hypotheses
H0: The average concentration is 300
H1: The average concentration is more than 300.
The null leads to one decision, the alternative leads to
another.
Question 2: Pew research found that only 30% of those born
in the lowest 5th of the economic ladder ever reach the middle 5th.
Is the success rate higher for those who earn a college degree?
H0: The proportion of people who move from the
lowest 5 to the middle 5th after getting a college degree is 0.30.
H1: The proportion of people who move from the
lowest 5th to the middle 5th after getting a college degree is greater
than 0.30.
th
The null leads to the conclusion the education does not help.
The alternative leads the conclusion that education helps.
3. Design the research (study or experiment)
4. Collect data
Research - An organized process through which unbiased evidence
can be gathered to determine which hypothesis is best supported.
Categorical and Quantitative Random Variables
Question 1:
Draw a sample from Excel – Methylmercury
Question 2:
Sample from bags
5. Use graphs and statistics measures to
explore the data
H0: The concentration is 300
H1: The concentration is more than 300.
These are histograms. Which hypothesis is supported by the left
histogram? Which by the right?
These are box plots of the same data. Which hypothesis does the
left box plot support? Which hypothesis does the right box plot
support?
H0: The proportion of people with a college degree
who move from the bottom 5th to the middle 5th is 0.30
H1: The proportion of people with a college degree
who move from the bottom 5th to the middle 5th is greater than 0.30
Based on a sample of 300 people who were in the bottom 5th in the
past.
Which hypothesis is supported by each of these?
What about by this one?
Bar Graph
Scatter Plot
Below is a time series plot of the percent of people under the
poverty line.
Parameters and Statistics for categorical and quantitative data –
Type of Data
Parameter
Statistic
Categorical
p – proportion of population
- proportion of sample
Quantitative
µ - Mean of Population
- mean of sample
Go to In-Class Activities- Proportions and Means – Page 268
Now we can write hypotheses as:
Question 1: Is the average tissue concentration more than
300g/kg? If it is, fishing will be prohibited.
Two hypotheses
H0: The concentration is 300
H1: The concentration is more than 300.
H0:  = 300
H1:  > 300.
Question 2: The Pew research found that only 30% of those
born in the lowest 5th of the economic ladder ever reach the middle
5th. Is the success rate higher for those who earn a college degree?
H0: The proportion of people with a college degree
who move from the bottom 5th to the middle 5th is 0.30
H1: The proportion of people with a college degree
who move from the bottom 5th to the middle 5th is greater than 0.30
H0: p = 0.30
H1: p > 0.30
For question 1, which hypothesis is supported if
x  280
x  780
x  310
For question 2, which hypothesis is supported if:
pˆ  0.26
pˆ  0.58
pˆ  0.32