Prediction vs. inference

The figure to the right contrasts two groups of simulated values for the reaction test game.

The top histogram displays simulated values of the mean reaction time M (from John's normal posterior density) and the bottom histogram graphs simulated values of the predictive density for the test score y.

Which statement best summarizes the difference between these two sets of simulated values?

Possible Answers

The two histograms have similar averages and spreads.
The two histograms have similar averages but the histogram of the predictive density of y has much larger spread.
The two histograms have similar averages but the histogram of the posterior density for M has much larger spread.
The averages and spreads of the two histograms are both significantly different.

Exercise

Prediction vs. inference

Instructions

Possible Answers