document.write( "Question 467235: Twenty students randomly assigned to an experimental group receive an \n" );
document.write( "instructional program; 30 in a control group do not. After 6 months, both groups \n" );
document.write( "are tested on their knowledge. The experimental group has a mean of 38 on the \n" );
document.write( "test (with an estimated population standard deviation of 3); the control group \n" );
document.write( "has a mean of 35 (with an estimated population standard deviation of 5). Using \n" );
document.write( "the .05 level, what should the experimenter conclude? (a) Use the steps of \n" );
document.write( "hypothesis testing, (b) sketch the distributions involved, and (c) explain your \n" );
document.write( "answer to someone who is familiar with the t test for a single sample but not \n" );
document.write( "with the t test for independent means. \n" );
document.write( " \n" );
document.write( "
![\"\"](\"/images/stars/stars-09.gif\")
