R Basics & Plotting
This R function reads a text file into a dataframe.
What is read.table()?
The IQR stands for this.
What is the interquartile range?
This measure is the midpoint when data are ordered from smallest to largest.
What is the median?
In a hypothesis test, this symbol represents the default assumption.
What is H₀ (null hypothesis)?
A correlation near -1 indicates this kind of relationship.
What is a strong, negative relationship?
The argument in plot(..., type="l") tells R to do this.
What is draw a line plot?
When P(A ∩ B) ≠ P(A)×P(B), the two events are this.
What is “not independent”?
This distribution has the mean and median equal and is symmetric.
What is the Normal distribution?
The t-test uses this distribution.
What is the Student's t-distribution?
This R function fits a linear model.
What is lm()?
In data$YEAR, the $ symbol means this.
What is “select a column from a dataframe”?
This R command finds the probability of being greater than X given a normal distribution.
What is 1-pnorm(X, mean, sd)?
In a histogram, changing this parameter alters how smooth or rough the shape appears.
A p-value less than 0.05 typically leads to this decision.
What is “reject the null hypothesis”?
This value tells you the percent of variability explained by a model.
What is R²?
This code will display the first 6 lines of a dataset.
What is head(data)?
This equation forms the y-axis of an empirical CDF (n = length of data).
What is (1:n)/(n+1)?
Outliers can affect this summary statistic more strongly than the median.
What is the mean?
This type of test compares two variances.
What is an F-test?
This R function tests whether model residuals are independent.
What is dwtest() from the lmtest package?
This R function orders data from smallest to largest.
What is sort()?
If A and B are events, this formula computes conditional probability, P(A|B).
What is P(A ∩ B) / P(B)?
This theorem says that if enough data of skewed distributions are averaged or summed, then those averages or sums make up a normal distribution.
What is the central limit theorem?
When only one direction is of interest (e.g., alternative hypothesis tests for “greater than”), this kind of test is used.
What is a one-sided (one-tailed) test?
This R function outputs the statistics of a linear regression model.
What is summary()?