Matched pairs: You get 2 measurements on the same unit (for example, before and after measurements or left-hand vs. right hand for everyone ) OR you have measurements on two sets of units, with each individual of one set being paired off (matched by some trait) with an individual of the other set. We will measure the difference between each pair, and on only ONE MEAN, the mean of these differences.

2-Sample Comparison of Means: You have 2 separate populations from which you get 2 independent samples, and you just measure each unit once (for example, men vs. women, or undergraduates vs. graduates), i.e. there are TWO MEANS and there is no valid reason to pair up the subjects.

snr_start: Signal to noise (SNR) measurements taken at the beginning of the semester for each student

snr_end: Signal to noise (SNR) measurements taken at the end of the semester for each student

bRmsAdd: Background RMS value for the add condition

isAthlete: Athlete status for the subject

Check the dataset variables description on Brightspace if you would like more details on the variables.

(1) Whether the population mean background RMS values for the add condition (bRmsAdd) is different between athletes and non-athletes (isAthlete).

(2) Whether for the population, SNR values taken at the beginning of the semester (snr_start) are less than SNR values taken at the end of the semester (snr_end).

The following lab will refer to these data ((a) and (b)) and questions ((1) and (2)).

1. (1 point) For which of the above questions would you use Matched Pairs to answer, (1) or (2)? Which dataset can be used to answer that question, (a) or (b)? How do you know?