This quantitative study explained relationships among independent variables that included instrumental music participation and achievement on a standardized test by participants in the ninth grade at a western Wisconsin high school. The ACT "Aspire" (2017) test is a vertically articulated, standards-based system of assessments. Subtest scores included in the regression analysis were: composite, English, math, reading, science and writing. Conclusions of this study were that instrumental music study exerted a statistically significant positive influence on the results of one standardized test. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]