The purpose of this study is to evaluate the effect of SCH 900271 compared to placebo on the reduction of low-density lipoprotein cholesterol (LDL-C) from baseline to 8 weeks of treatment in participants with primary hypercholesterolemia (familial and nonfamilial) or mixed hyperlipidemia. The study will also evaluate the effect of SCH 900271 on non-high density lipoprotein cholesterol (non-HDL-C) and various other lipids and lipoproteins. The safety of SCH 900271 in this participant population will also be evaluated.