A Researcher Is Interested in Whether Students Who Are Musicians

A researcher is interested in whether students who are musicians have higher intelligence test scores than students in the general population. The researcher predicts that playing a musical instrument is associated with higher intelligence test scores. The researcher selects a sample of 75 musicians from local high schools and gives them an intelligence test. The mean for the sample is 105. The mean for the general population (µ) is 100 with a standard deviation (s) of 15. What is z_obt for this sample?​

A) 0.33
B) 1.89
C) 2.89
D) 3.25