Hard Level 3

Question 1

Categorical vs quantitative data

Answer 1

Categorical if they fall into groups
Quantitative if they are numerical where you can average

• use bar graphs, pie, segmented
  Color and gender
• use dot plots, stem, histograms, boxplots
  Age and weight

Question 2

Unbiased estimator

Answer 2

A statistic is an unbiased estimator of a parameter if the mean of its sample distribution equals the true value of the parameter being estimated

The sampling distribution of the stat is centered in the right place

Question 3

Law of large numbers

Answer 3

If we observe many repetitions of a chance process the observed proportion of times that an event occurs approaches a single value called the probability of that event

Question 4

Confounding

Answer 4

Two variables are confounded if it cannot be determined which variable is causing the change in the response variable

Question 5

Outliers and influential points in regression

Answer 5

Any point that falls outside the pattern of the association

An influential point is an outlier that greatly affects the slope of the regression line.

Question 6

Benefit of blocking

Answer 6

Blocking helps account for the variability in the response variable that is caused by the blocking variable

Blocking will inc power