Question

Please answer a&b. I will thumbs up!

For each of the following studies, decide if the result was statistically significant and/or practically significant. Assume for each study that the significance level used was .05 (a) Based on a study published in Nature (Weber et al, 1998), a Reuters article on the Yahoo Health News website ran a headline Spring Birthday Confers Height Advantage (Feb 18, 1998). The article described an Austrian study of the heights of 507,125 military recruits. They tested the theory that the average height for recruits born in spring was greater than the average height of recruits born in the fall. They found a p-value < .0001. The difference in average heights was all of 0.6 centimetres, or about / inch. Statistically significant but not practically significant Statistically significant and practically significant Not statistically significant and not practically significant o Practically significant but not statistically significant (b) More evidence is being put forward that breastfed babies eventually become more intelligent than those who are fed with formula milk. Canada's McGill University found breastfed babies ended up performing better in IQ tests by the age of six, with the average score higher by 5.9 points than the average score of babies not breast fed. The p-value for their study was <.001. This study of nearly 14,000 children is the latest in a series of reports to have found such a positive link. Statistically significant but not practically significant Statistically significant and practically significant Not statistically significant and not practically significant Practically significant but not statistically significant

Answer 1

(a) The difference of height of 1/4 inches is not practically significant

P value of < .0001 (which is less than 0.05) is statistically significant

Thus it is Statistically significant but not practically significant

(b) P value of < .001(which is less than 0.05) is statistically significant

Also the difference of IQ score of 5.9 points is practically significant

Thus it is Statistically significant and practically significant