probability question The standard normal Z table at httpwwws

probability question

The standard normal (Z) table at http://www.sjsu.edu/faculty/gerstman/EpiInfo/z-table.htm contains, for each value of Z from 0 to about 3, the area under the standard normal curve N(0, 1) to the left of x = Z. As discussed in class, this area can be interpreted as the probability that a value selected at random from the standard normal distribution (mean µ = 0, standard deviation = 1) will be less than or equal to Z. Using only this table and the fact that any normal distribution N(µ, ) is a rescaling of the standard normal distribution, answer the following questions.

Question: Look at the table of 2013 SAT score percentiles at

Data: http://media.collegeboard.com/digitalServices/pdf/research/SAT-Percentile-Ranks-2013.pdf

Based on this table, assuming that no further re-centering or re-norming of scores has taken place since 1995, have students as a whole become better or worse at taking the test? Which section is currently “harder”: math or verbal? Justify your answers in light of the data in the table.

show your work!

Solution

as we can see with the scores, the students become better because the percentile are greater than the first test

the section crrently harder is math because they have less grades in that section than verbal