Results of survey on premarital sex of students from 38 classes by stratified cluster sampling in the Simmons model.

<p>Results of survey on premarital sex of students from 38 classes by stratified cluster sampling in the Simmons model.</p

Results of survey on cheating of students in 38 classes by stratified cluster sampling under the additive model.

<p>Results of survey on cheating of students in 38 classes by stratified cluster sampling under the additive model.</p