Chapter 1 Sections 1 & 2
Aug. 21, 2012Chapter 1Sections 1 & 2What is
statistics?Conducting studies to collect, organize, summarize,
analyze and draw conclusions from data.
Why study statistics?Pg. 3 Read numbers 1-3, briefly summarize
with your peer partner why study stats
Vocabulary..Variables: a characteristic or attribute that can
assume different valuesRandom variables: values are determined by
chanceData: the values the variables assumeData set: collection of
data valuesData value (datum): each value in the data set
Two main areas:Descriptive statistics: describes a
situationInferential statistics: makes inferences from samples to
populationsPopulation: all subjects that are being testedSample:
group of subjects selected from a populationExample:Our class is a
population. The brown haired students are a sample of the
population. Consider 17, 21, 44, and 76. Are those data?
A Consumer Reports article on energy bars gave the brand name,
flavor, price, number of calories, and grams of protein and
fat.Who?What?When?Where?How?Why?Try it..Pg. 5-6 Applying the
concepts 1-1Read the paragraph on attendance and grades and answer
the questions using complete sentences.BellringerRead The Worst Day
for Weight Loss on the top of p. 11. Then answer the questions
below.What are the variables under study?What are the data in the
study?Are descriptive, inferential, or both types of statistics
used?What is the population under study?Was a sample collected? If
so, from where?What is the relationship between the variables?
Variables and Types of data
Sort the data into at least 3 groups based on the type of data.
Be able to explain to the class why you grouped the data that
way.Section 2Types of DataQualitative (categorical) variables: can
be placed in distinct categories (ex. gender, geographic location,
race)Quantitative variables: numerical; can be ordered or ranked
(ex. Age, heights, weights)Discrete variables: countable variables
(can be assigned values 0,1,2,3.) (ex. Students in a room, number
of children)
Continuous variables: infinite number of values (ex.
Temperature, time)Levels of measurementThese four rankings from
lowest to highest are Nominal, Ordinal, Interval, and Ratio; Or its
easy to remember as NOIR.
Nominal: Data is in name only. There is no ranking system. ex.
Names, Ethnicity, Eye Color, Political Parties, Zip Code
Ordinal: There is a ranking but no numbers are used and the
boundaries are unclear.
ex. Small, Large; Poor, Fair, Good
Interval: The values are numerical and therefore can be ranked.
There is no absolute zero as a starting point.ex. IQ, Temperature,
SAT scores, Time (clock)
Ratio: The values are numerical and there is a starting point of
zero.ex. Speed, Money, Time (duration), Age, Weight
A plane technician wants to find out what the average weight of
carry-on luggage is for a passenger on a plane. He decides to weigh
the luggage of each passenger in line at a counter. The weights are
25, 15,4, 14,13,and 8 pounds each. What would be the population?
all the carry-on luggage for planes What would be the Sample? the
luggage of the people in line.What would be the variable?The weight
of the luggageWhat would be the data? 25, 15, 4, 14, 13, and 8 in
poundsWhat kind of statistic would this be? Inferential What kind
of variable are we measuring? Quantitative-continuous
A report on the Boston Marathon listed each runners gender,
country, age, and
time.Who?What?When?Where?How?Why?Variables?Qualitative?
Quantitative?
Applying the ConceptsPg. 9Read the information about
transportation industry and answer the questions using complete
sentences.Section 3Four basic sampling techniquesRandom sampling:
using chance methods or random numbersEx. Random number
generatorSystematic sampling: numbering each subject and then
selecting every kth personEx. 200 people in the room, asking every
5th personStratified sampling: Dividing population into groups
according to some characteristic that is important to the study.
Ex. Asking 5 freshman, sophomores, juniors, and seniors to rate the
cafeteria food as good, average, or poor. Sampling cont. Cluster
sampling: Divide the population into groups called clusters and
randomly selecting some of the clusters and using all members of
that clusterEx. X X X X X
Summarized tablePg. 13Summarized table of sampling methods
Applying the conceptsPg. 13Read the paragraph. Brainstorm with
your group the answers to the questions. Be prepared to have a
discussion with the class. Class Activity!Come up with as many
examples of the different types of sampling as you can. Work with
your peer partner. Make sure to pay close attention and describe
what your population is and who your subjects are. Be ready to
discuss them with the class. BellringerStudy the vocabulary terms
from sections 1-3 in chapter 1.Time for a quiz!
How did you studyNotes 10 studentsBook 4 studentsCards 4
studentsObservational and Experimental StudiesSection
1.4Observational StudiesResearcher simply observes what is
happening or what has happened in the past and draws conclusions
based on these observations. Ex. A research study comparing the
risk of developing lung cancer, between smokers and
non-smokers.There is no experimentFindings can be flawed due to
health background, diet, and exercise.Experimental StudiesOne of
the variables is manipulated to try and determine how the
manipulation influences other variablesIndependent variable
(explanatory variable)- the one being manipulated
(changed)Dependent variable (outcome variable)- variable studied to
see if it has changed due to the change in the independent
variable.
Ex. Placing different bill amounts on the ground and concluding
which one is more likely to be picked up.Problems with experimental
studiesHawthorne effect: subject who know they are participating in
an experiment change behavior in ways that affect the study
Confounding of variables: influences the dependent variable but
is not separated from the independent variableEx. Exercise program
testing the program results but not controlling what the
participates diet consists of Time to think..Read starting at the
last paragraph of p.14-16.
What are advantages and disadvantages of each type of study?What
is the Hawthorne Effect? Why do you think this happens?What is a
confounding variable? How is this a problem in experimental
studies?Why might two studies on the same subject yield conflicting
results?
Do #1-7 on p. 16Uses and Misuses of StatisticsSection 1.5Read
Suspect Samples p. 17Complete the table for suspect samplesType of
MisuseWhat does it mean?What are the problems?Suspect
samplesAmbiguous averagesChanging the subjectDetached
statisticsImplied connectionsMisleading graphsFaulty survey
questionsRead Ambiguous Averages and Changing the Subject p.
17-18ReadDetached StatisticsImplied ConnectionsRead Misleading
graphs and Faulty Survey QuestionsCollect some data..What
conclusions can we assume from the data collected from the class?Is
are assumption a use or misuse of statistics?Have chart drawn on
board for students to fill in. Gender, age, shoe size, height,
sports31
