Variables and Relationships
A variable whose values are numbers that represent amounts or quantities.
What is a numerical variable?
Sampling method in which each case in the population has an equal chance of being included and there is no implied connection between the cases in the sample.
What is a simple random sample?
Two events that cannot both happen simultaneously.
What is disjoint/mutually exclusive?
A random variable that counts the number of successes in one trial, where each trial has two possible outcomes, follows this distribution.
What is a Bernoulli distribution?
In a Normal distribution, this value marks the center of the curve.
What is the mean?
A variable that might causally affect another.
What is an explanatory variable?
The percentage that fits the following question: "If Q1 = 8% and Q3 = 14%, what is the IQR?"
What is 6%?
Number that answers the following question: "What is the probability of rolling a 1 or a 2 on a fair-sided die?"
What is 1/3?
A random variable that counts the number of successes in a fixed number of independent trials follows this distribution.
What is a Binomial distribution?
In an approximately Normal distribution, about this percentage of observations lie within one standard deviation of the mean.
What is 68%?
A numerical variable whose values can be counted.
What is a discrete variable?
Sampling method that matches the following example: A political survey is done by stopping people walking in the Bronx.
Number that answers the following question: "If P(A) = 0.2, P(A and B) = 0.1, and P(A or B) = 0.4, what is P(B)?"
What is 0.3?
A random variable that counts the number of trials until the first success follows this distribution.
What is a Geometric distribution?
A commute time is 10 minutes below the mean in a Normal distribution with a standard deviation of 5 minutes. This is its z-score.
What is z=-2?
A variable that is correlated with both the explanatory and response variables and causes an association when there is not one.
What is a confounding variable?
A data set in which the mean is less than the median.
What is skewed left?
Formula for the conditional probability of outcome A given condition B.
What is P(A|B) = P(A and B)/P(B)?
A fair coin is flipped until the first head. This is the probability that the first head occurs on the third flip.
What is 1/8?
For a Standard Normal random variable Z, this is P(Z < 1).
About 0.8413?
A categorical variable whose categories have a meaningful order.
What is an ordinal variable?
Number the answers the following question: "Consider a contingency table with homeownership (rent/mortgage/own) in the first row and application type (individual/joint) being the first column. If the number of individuals who rent is 3496, the number of overall renters is 3858, and the number of total individuals is 8505, what is the row proportion for individual/rent?"
What is 3496/8505 = 0.411?
Number that answers the following question: "Consider flipping a fair coin, what is the probability that the first heads occurs on the third trial?"
What is 0.125?
What is 1.1?
A Normal distribution has mean 70 and standard deviation 8. What is the value at the 90th percentile?
What is 80.24?