One year, there were about 3,000 institutions of higher learning in the U.S. (including junior colleges and community colleges).
As part of a continuing study of higher education, the Carnegie Commission took a simple random sample of 400 of these institutions. The average enrollment in the 400 sample schools was 3,700, and the SD was 6,500. The Commission estimates the average enrollment at all 3,000 institutions to be around 3,700; they put a give-or-take number of 325 on this estimate. There were about 600,000 faculty members at institutions of higher learning in the U.S. As part of its study, the Carnegie Commission took a simple random sample of 2,500 of these faculty persons. On the average, these 2,500 sample persons had published 1.7 research papers in the two years prior to the survey, and the SD was 2.3 papers. If possible, find an approximate 95%-confidence interval for the average number of research papers published by all 600,000 faculty members in the two years prior to the survey. If this isn't possible, explain why not.
Thus an approximate 95% confidence interval for the average enrollment of all 60,000 faculty members in the two years prior to the survey. which implies that the given statement is true.
According to the statement
Average sample =3700
SD sample =6500
Sample size =400
EV average =3700
SE average =325
Population size =3000
The boundaries of the 68% confidence interval are then 1 standard error from the estimated average:
EV average+1⋅SE average =3700+1⋅325=3700+325=4025
EV average−1⋅SE average =3700−1⋅325=3700−325=3375
Thus an approximate 95% confidence interval for the average enrollment of all 60,000 faculty members in the two years prior to the survey. which implies that the given statement is true.