Sampling Methods and Bias
A researcher wants to know the proportion of household cats in the United States that are polydactyl cats (cats with extra toes), the researcher wants to know what sampling method they should use to make sure they survey households from each state
What is stratified random?
y-intercept
What is “the predicted [y-context] when [x=0 context] is [y-intercept]”?
Last year the mean number of blobfish per country was 10. A researcher wants to look into 17 countries this year and is interested in whether the mean number of blobfish per country has changed
What is 1 sample t-test for population mean?
Statistically significant
What is results are unlikely to occur purely by chance?
Probability of A and B
What is P(A) x P(B)?
A school principal, who is a weevil that has won 2 Nobel Prizes in each category despite being a 3mm large bug, wants to know how many students eat fast food for lunch at a particular high school, the principal wants to know how they can collect a simple random sample of all students at the high school
What is number all students and use a random number generator?
OR
What is write all students names down on pieces of paper and draw names?
Slope
What is “for each additional [X context] the predicted [Y context] increases/decreases by [slope]”?
How likely are people who see a giraffe on the side of the road to take it home? 200 people were surveyed to answer this question
What is 1 sample confidence interval for a proportion?
Residual
What is the prediction error?
Probability of B given A (if A and B are independent)
What is P(B)?
A researcher wants to know how many people in Florida have fed an alligator, but they only sample individuals at the local Jimmy Johns leading to this bias
What is convenience bias?
Confidence interval
What is “we are []% confident the true [context] is between the intervals [] and []”?
A person currently residing on the exoplanet Kepler-69c will try to kick a soccer ball into a goal 30 times with a 0.4 probability of making a goal, assume each trial is independent. The person wants to know the probability of making 28 out of 30 soccer balls into the goal
What is binomial?
Experimental unit
What is what/who treatment is imposed on?
Probability of A or B (if mutually exclusive)
What is P(A) + P(B)?
A city wants to know how people feel about the new mayor, who is actually 5 geese disguised under a trench coat and sunglasses. So they send out a survey by mail where individuals who fill it out must bring it to the city courthouse, located on the top of a mountain. They are worried this survey decision might lead to this bias
What is non response bias?
Residual
What is “the actual [context] was [residual] above/below the predicted value for [X]”?
Are average test scores higher when a therapy dog is present? To answer this question researchers asked 400 students to take a test with a therapy dog present and a test without
What is paired sample t-test?
Mutually exclusive
What is cannot occur at the same time?
Probability of B given A (if A and B are not independent)
What is P(A and B) / P(A)?
A researcher wants to know the average number of koalas in Canberra (Australia) who would ask for a water cup but then fill it with soda. When taking the sample the researcher wants to randomly select 2 restaurants and survey all koalas in the restaurants, leading to this sampling method
What is cluster?
Significance Test
What is “assuming the null hypothesis is true there is a [p-value] probability of getting a sampling distribution of [p hat] or more extreme purely by chance.
Because [p-value] is greater/less than [alpha], we fail to reject/reject the null hypothesis and do not/do have convincing evidence for the alternative hypothesis.”?
A restaurant is having a 20% off deal on Dr. Pepper, each customers order is independent and there is a .8 probability of ordering a Dr. Pepper. The restaurant wants to know the probability that the 5th customer to order is the first to order a Dr. Pepper
What is Geometric?
Continuous random variables
What is has infinite values with no gaps over a specific range?
Probability of A or B (if not mutually exclusive)
What is P(A) + P(B) - P(A and B)?