x = y3 and y > 1
Two different children are to be selected at random from a group of 12 students. If the probability that both students selected are girls is greater than , there must be at least how many girls among the 12 students?
Are you feeling incredibly stressed out when you sit down to study for the GRE? (Or maybe I should ask, who isn’t?) Do you find it hard to concentrate on the task at hand?
Researchers at the University of California at Santa Barbara recently published the results of a study following 48 undergrads preparing for the GRE. Jan Hoffman details the research in a blog post over at The New York Times; here’s a summary:
“We had already found that mind-wandering underlies performance on a variety of tests, including working memory capacity and intelligence,” said Michael D. Mrazek, (quoted from the NYT blog post)
Ah, yes, “mind-wandering.” We’ve all had this experience. We’re taking a test, the clock is ticking, and we keep finding ourselves thinking about something other than the question we’re supposed to be answering right now. Maybe we’re stressing about our score. Maybe we’re thinking about applications. Maybe we’re even distracted by work, significant others, family, or other issues that have nothing to do with the test!
How do we stop fixating on other things and concentrate on the task at hand? This study tried to find out.
First, the students were given one verbal reasoning section from the GRE. They also completed a task that measured their working memory. These tests are the “baseline” results.
The students were split into two groups; let’s call them Group M and Group N.
Group M attended meditation classes four times a week; these students learned lessons on “mindfulness,” which focuses on breathing techniques and helps to minimize distracting thoughts.
Group N attended nutrition classes, designed to teach these students healthy eating habits.
Afterwards, the students were given another GRE verbal section and another task to measure working memory. The performance of students in group N stayed the same; the nutritional studies didn’t make a difference.
Group M students, however, improved their GRE scores by an average of 12 percentile points! Here’s the best part: the study took just two weeks. You read that correctly: these students improved their verbal scores by 12 percentile points in just two weeks.