(1.95) Improving SAT scores. The National Education Longitudinal Survey (NELS) t
ID: 3354272 • Letter: #
Question
(1.95) Improving SAT scores. The National Education Longitudinal Survey (NELS) tracks a nationally representative sample of U.S. students from eighth grade through high school and college. Research published in Chance (Winter 2001) examined the Standardized Admission Test (SAT) scores of 265 NELS students who paid a private tutor to help them improve their scores The table below summarizes the changes in both the SAT-Mathematics and SAT-Verbal scores for these students. Assume that both distributions of SAT score changes are approximately normal. 3- SAT-VERBAL Mean Standard deviation SAT-MATH 19 65 49 What is the probability that a student increases his or her score on the SAT-Math test by at least 50 points? What is the probability that a student increases his or her score on the SAT-Verbal test by at least 50 points? a. b.Explanation / Answer
a) as for normal distribution ; z zscore =(X-mean)/std deviation
therefore probability that increases score on math test by at least 50 points =P(X>50)=1-P(X<50)
=1-P(Z<(50-19)/65)=1-P(Z<0.4769)=1-0.6833 =0.3167
b)
probability that increases score on verbal test by at least 50 points =P(X>50)=1-P(X<50)
=1-P(Z<(50-7)/49)=1-P(Z<0.8776)=1-0.8099 =0.1901
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.