Vocabulary
A numeric summary of a sample
Statistic
"This vitamin made my hair grow 6 inches in 3 months!"
Designed, Observational, or Anecdote
Anecdote
n
Sample size
Parameter
Another name for the dependent variable of interest
Response
A researcher is doing a study on whether music during studying improves test scores. They get 30 students and randomly assign 15 to the music group and 15 to the non-music group.
Designed, Observational, or Anecdote
Designed experiment
P (big P)
Population Proportion (Categorical Parameter)
A school district randomly selects 120 high school students and records how many hours each student slept the night before. The students slept an average sleep time of 6.8 hours.
What is the statistic?
x-bar = 6.8 hours
Another name for the explanatory variable of interest
Factor
In an experiment, I am going to give different pain medications to different groups. Pain med type would be a ___________. Asprin, Tylenol, and Ibuprofen would be __________.
Factor; levels of the factor
x-bar
sample mean/average (numerical statistic)
A university wants to estimate the proportion of undergraduate students who own a laptop. 300 undergraduate students are randomly selected and asked whether they own a laptop. 264 students reported owning a laptop.
What is the Parameter?
P = the true proportion of laptop owners at the university
Another name for the levels of the factor
Treatment
A researcher wants to know the average number of hours GVSU students sleep each night. She randomly selects 100 GVSU students and asks them how many hours they slept last night. The 100 students report an average of 6.8 hours.
What is the sample:
The 100 GV students the researcher talked to
p-hat
sample proportion (categorical statistic)
A coffee shop manager wants to know the proportion of customers who prefer iced coffee over hot coffee. To estimate this, the manager surveys 80 randomly selected customers during one week. Out of the 80 customers surveyed, 52 say they prefer iced coffee.
What is the population?
All customers at the coffee shop this week
Describe to the difference between an observational and experimental unit
Observational unit: smallest unit that gives a response
Experimental unit: smallest group in which treatments are applied to
Describe to me the pros and cons of observational studies and designed experiments.
(Hint: what is lacking in the results of one)
Observational studies: cheaper and easier to do, cannot show causation
Designed experiment: expensive, can run into ethical issues, CAN show causation
mu
population mean/average (numerical parameter)
A professor wants to know the percentage of students in her statistics class who own a car. She asks every student in the class, and 72% say yes.
the number 72% is a...
Parameter