Quiz 12.3
Chapter 12  Day 4
Students Struggled With…

Remembering what needed to be checked for each of the five conditions.

Understanding the difference between a residual plot and a dotplot of the residuals.

Mixing up the slope and yintercept from computer output.
Remedies…

(Condition)  how to check it > SO WHAT?

(Linear)  scatterplot linear or residual plot with no leftover pattern > so there is a fairly linear relationship between x and the mean of y.

(Independent)  10% condition > so sampling without replacement is OK

(Normal)  dotplot of residuals is approximately normal > so for each x, the distribution of y is approximately normal.

(Equal Variance)  residual plot shows similar size residuals for each xvalue > so for each x, the standard deviation of y is the same.

(Random)  random sample or random assignment > so we can generalize to the population or we can show causation.

Remind students that statisticians use y = a + bx rather than y = mx + b. It makes sense that the computer output would give us the yintercept first. hey should calculate a zscore and find the area above it.