R Commands

Question 1

What does the lm command do?

Answer 1

Produces estimates that minimise the squared difference between the observed data and the values returned by the model. (Least Squares)

Question 2

What does the Anova command do (not anova)?

Answer 2

Gives p-values for all predictions in a multiple regression model.

Question 3

What does the dredge command do? (MuMIn library)

Answer 3

The best model (by AICc) is at the top, gives all possible subsets.

Question 4

What does the crPlots command do?

Answer 4

Plots partial residuals.

Question 5

What does the cor command do?

Answer 5

Calculates r, the correlation coefficient.

Question 6

What does the cor.test command do?

Answer 6

Gives confidence intervals for ρ, the unknown population correlation coefficient.

Question 7

What does the summary command show?

Answer 7

Min. 1st Qu. Median. Mean. 3rd Qu. Max.

Question 8

What does the boot.ci command do?

Answer 8

Calculates bootstraped confidence intervals.

Question 9

What does the t.test command do?

Answer 9

t.test.

Question 10

pt(q, df=30, lower.tail=TRUE) ??

Answer 10

Calculates a probability p, that X is less than/equal to q.

Question 11

qt(p, df=30, lower.tail=TRUE) ??

Answer 11

Returns a quantile q associated with probability p.

Question 12

dt(x, df=30) ??

Answer 12

Calculates the density at value x from a t(df=30) distribution.

Question 13

rt(n, df=30) ??

Answer 13

Generates n random observations from a t(df=30) distribution.