Population: The entire group that is being studied (ex: Mt. Tabor Students)
Parameter: What is being studied for the population (ex: Heights of Mt. Tabor students)
Sample: A smaller group that represents the larger group (ex: 50 students of Mt. Tabor)
Statistic: What is being studied of the smaller group and/or the facts of the smaller group (ex: Average height of 50 Mt. Tabor
students is 68 inches>)
Example: You are trying to figure out the percentage of all green MM’s that are produced. You select 100 random MM’s and find
that 15.2% are green
Population: All MM’s made.
Parameter: Percentage of green MM’s of all MM’s
Sample: 100 MM’s
Statistic: Percentage of green MM’s of 100 or 15.2% of the MM’s are green
Correlation vs Causation:
Correlation: Observing that as something increases/decreases then the other increases/decreases.
Causation: One thing causes another thing to increase or decrease
Just because you have correlation, you don’t necessarily have causation
Example 1: You notice that as more people wear shorts, the temperature rises. Number of shorts don’t cause the temperature to
rise
Example 2: When John wears his lucky hat, he scores at least 120 points in bowling. Green hat doesn’t cause him to bowl better.
Ways of examining data:
Survey: Asking questions. Good for find out preferences.
Observational Study: Analyzing data or observing people. Good for finding correlation but not causation
Experiment: Looking at the cause and effect of two groups in which one group is affected. Good for causation.
Identify the best to examine the data
Finding the GPA’s of the football team: Survey or observational study (look it up)
Predicting who will win the election: Survey
Finding out if using the computer causes better grades: Experiment (looking for causation)
Methods of Sampling:
Convenience: Selecting the sample by what is convenient. (Ex: Standing in front of cafeteria, asking this class only) Can be
unbiased if there is a significant difference between the group you are studying from the population.
Random: Randomly choosing numbers out of a hat.
Systematic Random: Assigning random numbers (or using random numbers) and then selecting every 5 th number. It’s best if you
choose where you start from.
Stratified: Choosing random people from each natural groups (Ex: 5 males and 11 females) Best for polling to ensure that you get
fair representation from the population.
Cluster: Randomly assigning unnatural groups (A,B,C.. etc), selecting a group, and then people from that group.
(Ex: Randomly assign people to A,B,C,D. Then randomly choose C. Then choose 20 members from C)
You are doing an experiment to see if a flea spray works on animals. You want to choose 50 animals from a population of 150 dogs
and 100 cats.
Convenience: Selecting 50 dogs
Random: Randomly choosing an animal
Systematic Random: Assigning all 250 animals a random number and then selecting every 5 th number
Stratified: Randomly selecting 30 dogs and 20 cats
Cluster: Assign each animal a group of A,B, or C. Then choosing B. Then randomly selecting 50 animals from B.
1.
You are trying to determine the amount of miles that the 400 residents (100 on each floor) at a senior citizen home walk
each day. You randomly select 80 senior citizens. You find that the 80 senior citizens walk an average of 0.8 miles. Identify
the following:
Population:________________ Parameter:_________________________________________________________
Sample:___________________ Statistic:___________________________________________________________
Determine whether each research study is a survey (S), observational study (O) or an experiment (E). Identify the
factor if it is an observational study or the treatment if it is an experiment. Also identify the characteristic of interest.
2. Giving each person a pedometer for one day and then looking at the results
3. Asking each person how far they walked.
4. Assigning 40 members to wear slippers and 40 members to wear tennis shoes. Then give each person a pedometer and try
to determine if people with tennis shoes are more likely to walk more.
5. Determining if people who eat breakfast causes them to walk more during the day
6. You are trying to show if there is a difference between the distance that a male and a female walks.
7. Mr. Smith has 100 subjects with high cholesterol take fish oil pills daily for two months. They monitor the cholesterol of the subjects
during that time.
8. Suppose you wanted to know how much people sleep on average each night?
9. Suppose you wanted to know if people who wear red shirts are clumsier than other students.
10. Suppose you wanted to find out if smoking causes cancer.
Identify the best sampling method. Convenience (C), Random (R), Systematic Random (S), Stratified (F) or Cluster (L)
11. Randomly selecting 20 members from each floor
12. Randomly choosing room numbers from a hat.
13. Assigning each resident a group of A,B,C, D; selecting group A; and then choosing 80 members
14. Looking at roster of names and selecting every 5th name. (You randomly decide with the 2nd name.)
15. Asking 80 members from the 4th floor.
16.
A.
B.
C.
D.
Which of the following would probably be a causation:
The people on the lower floor tend to walk more than those on the upper floor.
Males are more likely to walk more than females
The younger a person is causes them to walk more
People who wear yellow are likely to walk more.
Explain why the results of each survey are likely to be inaccurate and then suggest a way to improve the accuracy of the survey.
17. Mr. Wonsavage, the owner of WonWon’s Burger Shack, conducts won-on-won interviews with a random sample of employees to
have them rate how satisfied they are with different aspects of their jobs.
18. In a random sample of residents of Wontropolis, a survey asks, “Are you in favor of a special tax levy to renovate the dilapidated
town hall?”
19. If the survey was revised in #18 to give a factual list
of repairs that need to be made to the town hall, do
the people have enough information to give an
informed and accurate response? Why or why not?
Evaluate the following article from “Daily Won” about the
effect of doctor empathy on the duration and severity of a
“wondition”.
20. Is this a survey, an observational study, or an
Experiment? How do you know?
21. Was randomization used in the research? If so,
how?
22. What conclusion do you draw from the report?
How much confidence do you place in that conclusion?
Why?