Thecounsellors made a type 2 error. A type 2 error is made when asignificance test occurs and results in the rejection of a true nullhypothesis. The random sample they used was not fully representativeof all the freshmen, it overrepresented those with high scores andunderrepresented those with low scores. The conclusion that thefreshmen class is indeed the brightest is incorrect since theinformation used was biased.
Astudy in which researchers want to test whether there is a differencein spatial ability between left and right-handed people is a 1-tailedtest. The appropriate null hypothesis is “There is no differencebetween the spatial ability of right and left handed people”. Thealternative hypothesis is “There is significant difference in thespatial ability of right handed people and left-handed people”.
Astudy in which researchers want to test whether nurses who work8-hour shifts deliver higher-quality work than those who work 12 hourshifts is a 2-tailed test. A 2-tailed test is a test of significanceto determine if there is a relationship between two variables ineither direction. The appropriate null hypothesis is “There is nodifference in work-quality between nurses who work 8-hour shifts andthose who work 12-hour shifts”. The alternative hypothesis is“there is a difference in work-quality between nurses whowork8-hour shifts” (Kantowitz,Roediger & Elmes, 2015).
Astudy in which researchers want to determine if crate-trainingpuppies are more superior to training without a crate is a 1-tailedtest. The null hypothesis is “crate-training puppies is not moresuperior to training without”. The alternative hypothesis is“crate-training puppies is more superior to training without acrate”.
Kantowitz,B. H., Roediger, H. L., & Elmes, D. G. (2015). Experimentalpsychology.John Wiley and Sons, New Jersey.