The National Assessment of Educational Progress (NAEP) comprises a "long-term trend" study that tracks reading as well as mathematics skills over time and obtains demographic information. In the 2008 study, a random sample of 9600 17-year old students was chosen. The NAEP sample employed a multistage design, but entire the effect is quite similar to an SRS of 17 year olds who are still in school.
a) IN the sample, 46% of students had at least one parent who was college graduate. Determine with 99% confidence the proportion of all 17 year old students in 2008 who had a least one parent who was a college graduate.
b) The sample does not include 17 year olds who dropped out of school, so your estimate is valid only for stuents . Do you think that the proportion of all 17 year olds with at least one parent who was a college graduate would be higher or lower than 46 % ? explain.