. jane has developed a new happiness questionnaire. to demonstrate its scientific merit, she uses it to measure happiness in 10 couples who have just started dating. she asks each participant to complete a happiness questionnaire. she waits a year, then attempts to re-contact each of the couples to ask them to complete the questionnaire again. jane then calculates the pearson r correlation coefficient between happiness levels at the outset of her study and one year later. what scientific standard is jane evaluating?