Predictors of First-Year Chemistry Grades for Black Americans J. W. Carmichael,. Jr..' . Sr. Joanne Bauer,' John P. Sevenair,' Jacqueline T. Hunter? and Richard L. GarnbrelP Xavier University of Louisiana, New Orleans, LA 70125 Black Americans are severely underrepresented in the natural and health sciences. For instance, while census studies show that black Americans constitute almost 12%of the nation's population (I), the National Science Foundation reports that less than 2% of the nation's scientists are black (2). The percentage of black health professionals in the United States is equally low (3). While underrepresentation of black Americans (or any other minority group) in any profession is of concern, it is of special importance in the natural and health sciences. First, the lack of minorities in these fields is si~nificantbecause it impinges im the quality and availability of primary health care in minority communities ( 4 ) .Second, the lack of minorities in the natural and healrhscirnces lendscredence w t h e fear that minorities will he excluded from key decision makingin our increasingly technological world. ~ h i r dthe , lack of minorities in these areas denies society the untapped resources of minority groups and thereby weakens the nation as a whole. In view of these factors, continued efforts are needed to increase the number of hlacks in the sciences. If there is to be significant progress toward reaching the goal of increasing the number of black Americans in sciencerelated fields, both predominantly black and majority institutions must be involved in the effort. The potential role of the predominantly black institutions is indiiated by the fact that while they enrolled only 17% of hlack Americans in college in the late 1970's (51,they awarded 37% of the baccalaureate degrees received by hlacks nationwide and more than 50% of such degrees in states where the traditionally black colleges were located (6). Of particular value in the effort to increase the access of hlacks to science-related careers are studies of factors which impinge upon achievement of blacks in mathematics and science courses. This paper describes one such effort, a study of predictors for succ& of hlack Americans in freshman chemistry a t Xavier University of Louisiana, a small, predominantly black institution in New Orleans. I t is one of a number of studies under way to identify factors which lead to success in the sciences a t this University.
' Department of Chemistry Department of Biology. Institutional Research.
Overvlew Xavier University of Louisiana (XU) and its first-year chemistrv. seauence are rather unusual. XU is a Catholic, . liberal arts insritution with a required core curriculum of 46 hours nutsidr of mathematics and ncicnce. Enrollment of full-time undergraduates, of whom approximately 90% are black Americans, has remained between 1,600 and 1,700 for a number of years. The percentage of students in sciencebased programs has grown dramatically to become almost 213.of in the United -. . the total enrollment. XU is now States in placing black Americans into colikges of pharmacy, one of the top five schools in the nation in placing hlacks into medical schools, and a significant supplier of blacks for science graduate schools. Chemistry has heen a leader in this growth. In 1983-84, XU'S Chemistry Department had 228 maiors and produced 27 maduates, of whom 21 were accepted into graduate or prof&sional school. XU'S only first-year chemistry courses are intended for students majoring in the sciences. The two-semester sequence has many unusual features specifically designed to meet the needs of the underorenared ---... . . students. Detailed descriptions of the two-semester sequence have appeared ~reviouslv . (7.8). . , . Under the eeneral ohiloso~hvof focusing &exit rather than entrance criteria, ihe cou&eis structured so as to combine high academic standards, comprehensive academic support for all students, and development of a Deer e u a w r t svstem. ~rrvi('usattempts to identify accurate predictors of grade in first-year chemistry have considered traditional criteria such as high school grade point average, high school chcmistry gradt,, and mathematics SAT score (0-111 as well as less traditional oredictors such as I'iaeetian develoumrntal level (12,13). Other studies (14-16) inchate that triditional variables predict college grades of hlack students a t predominantly black colleges, and at least one study finds that there is a significant relationship between scores on the NelsonDenny Reading Test and grades of black freshmen college students (17). This trend of successful prediction is broken in two areas, however. First, the traditional criteria predict the performance of black students a t predominantly white institutions rather poorly (18.19). Second, there is evidence that traditionnl criteria are less usetul in predicting the academic performance of hlack males than that of black females ~
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Volume 63 Number 4
April 1986
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These studies suggest a number of questions to consider in the present investigation. Can traditional variablespredirt performanceof black Amerifirst-year rhcmistry at a traditionally black institution? If so, what is the predictive procedure? 2) How does predictive power for black males vary from that for black females? 3) What implicationscan bedrawn from comparison of this study ' , with past investigations? 11
e m s in
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Procedure First-year chemistry a t XU,is a two-semester sequence composed of Chemistry 1010' and Chemistry 1020. Ten readily available, traditional variables found to have predictive power in the studies cited above were chosen for study as potential predictors of grade in Chemistry 1010. They were High school grade point average ((;PA) on a 4.0 scale. Cumporitt. swre on the American Cdlege Testing Program I.\CTJand scurci on the four sul,sectionr tmathematic~.English, natural science, and social science) on the established 1 to 36 scale. Scorrs on the thrre portlonuofthe Nelson-Denny Readmg Test tvucab~ridry,romprchcns~on,and total) In terms of grade level equivalents, and Sex of student. The . nonulation under studv consisted of 236 students . (155 females and 81 males) entering the University as freshmen and majoring in biology, chemistry, or pharmacy in the fall semesters of 1981 or 1982. This is approximately twothirds of the total enrollment in general chemistry for these two years. The remaining students either did n i t present ACT scores, entered XU in an earlier year, or were majoring in other fields. Of the Chemistry 1010 enrollment, 177 students (107 females and 70 males) subsequently enrolled in Chemistry 1020 and were used in the analysis of that course. Predictors of Grades in Chemistry 1010 and 1020 Analysis was performed using the Statistical Package for the Social Sciences (SPSS)-Version 9. First. means and standard deviations were obtained for all variables associated with Chemistry 1010 and 1020. Numerical values were substituted for the alphabetical values of Chemistry 1010 grades (A = 4, B = 3, C = 2, D = 1, and W or F = 0) and a dummy variable was introduced for sex (Male = 1and Female = 0). The grade in Chemistry 1010 was added to the list of Chemistry 1020 predictive variables. Results are summarized in Table 1. While the numerical values are generally self-explanatory, some observations might be made. The 17.6 mean of the ACT comnosite scores for students in Chemistrv 1010 is comparahie to the mean of freshman in the ~ o u t l k e s and t Sourh Southeast (22)and reading scores are at the e x ~ e r t e d 13th grade level. The mean for sex (0.34) reflects the fact that approximately one-third of the students were male. This distribution by sex is typical of the enrollments in general chemistry at XU and a t the University as a whole. The increase in the dummy sex variable from Chemistry 1010 to Chemistry 1020 reflects the fact that attrition of females was hieher than that of males. The increase in the means of the ackemically related variables is not surprising, since normal academic selection would be exvected to eliminate more of those with lower scores. Next, Pearson correlation coefficients between Chemistry 1010 and 1020 grades and each of the potential predictor variables were calculated. These correlations are presented in Table 2. All correlation coefficients except those for Nelson-Dennv comprehension and sex are sufficiently large to have use ih predicting grades in Chemistry 1010, with ACT Composite score being the best single predictor. Approximately 30% of 334
Journal of Chemical Education
the variance (r2 X 100) in Chemistry 1010 grade can be explained by variance in ACT Composite score. The data for Chemistry 1020 show that the grade in Chemistry 1010 is a particularly good predictor. High school grade point average, ACT Composite, and some of the other variables also have predictive power, though in most cases the correlation coefficients are smaller than those for Chemistry 1010. Multiple linear regressions (best least-squares fit of a straight line in multi-dimensional space) were completed for both Chemistry 1010 and 1020. Variables were added one a t a time so as to obtain the maximum increase in the multiple correlation coefficient R a t each sten. until addine more terms failed to produce a statisticall; kignificant improvement a t the 0.05 level. Before performing this analysis, the components of the ACT and of the Nelson-Denny Reading Test were d r o ~ v e dfrom consideration. The high - degree - of correlation beikeen the composites and their respective components indicated that comvosites and components were so interdependent that regression procedures might not he applicable. Subsequent multiple linear regression analyses using components rather than compositesierified that use of components did not improve predictive power. The results of the linear reeression with four ~redictive variables (high school grade &in1 average, ACT 6ornposite. Nelson-Dcnnv Reading Total. and sex) are summarized in Tahle 3. The Final rol&n in that table indicates the probabihtv tie) that theohserved relations hi^ occurred by chance. F& chemistry 1010, adding high school grade point average to ACT Composite increases R to 0.625 while variance in grade explained increases by 9%, to 39% of the total. Taking the sex variable into account further increases R to 0.644. The remaining variables did not produce a statistically significant increase (at the 0.05 level) in predictive ability when Table 1. Means and Standard Devlatlons ol Predictors for Students In Chemistry 1010 (N = 236) and Chemistry 1020 ( N = 177)
Variable
Chemistry 1010 Chemistry 1020 Standard Standard Mean Deviation Mean Deviation
Chem 1020 Grade Chem 1010 Grade High School GPA ACT Composite ACT English ACT Mathematics ACT Natural Science ACT Social Science Nelson-Denny Vocabulary Nelson-Denny Comprehena Nelson-Denny Totai Sex
Table 2. Correlation Coefflclents ( r ) Between Chem 1010 and Chem 1020 Grades and Each of the Independent Variables lndepedent Variable Chem 1010 Grade High School GPA ACT Composite ACT English ACT Mathematics ACT Natural Science ACT Social Science Nelson-Denny Mcabuiary Nelson-Denny Comprehension Nelson-Denny Total Sex
,with
rwith
Chem 1010
Chem 1020
... 0.494 0.547 0.488 0.477 0.443 0.419 0.419 0.219 0.413 0.063
0.671 0.505 0.407 0.393 0.356 0.331 0.253 0.349 0.333 0.373 -0.175
added. The unstandardized predictive equation for Chemistry 1010 was found to he
where Y = Predicted Chemistry 1010 grade with A = 4, B = 3, C = 2, D=l,andWorF=O X , = ACT composite score X, = High school grade point average X3 = Dummy variable for sex with Male = 1and Female = 0
The linear regression for Chemistry 1020 indicates that only one variahle, high school grade point average, produces a statistically significant increase in the ability of Chemistry 1010 grade to predict Chemistry 1020 grade. The unstandardized predictive equation was found to he:
where Y = Predicted Chemistry 1020 grade on a "4 to 0" scale as indicated above X, = Chemistry 1010 grade on the "4 to O" scale X, = High school grade point average
Next. since ~ r e v i o u sinvestieations have indicated that traditional criteria were less useful in predicting the academic performance of black males than of hlack females (20, 21), separate multiple regression analyses were run for each. In Chemistry 1010, ACT Composite was the best predictor for hoth sexes, yielding R = 0.552 for females and R = 0.557 for males. Subsequent addition of high school grade point averaee ~" in asecond sten increasedR to 0.642 for females and 0.655 formales. ~ d d i t i b nof other variahles made no statistically significant improvement in R in either case. For Chemistry 1020, the analyses yielded multiple correlation coefficients of 0.676 for males and 0.678 for females. ~
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I ) Con rroditional vanablespredict pwforrnonroof hlock Amer. i~onsin first-yearch~rnirtrsat a rrudilior,olly hlork tnsittrticm! I1 so, what is the predictiue procedure? Table 1indicates that almost all of the traditional predictive variahles under consideration have reasonable predictive value for grade in the first semester of chemistry a t Xavier and that some have such value for the second half of the course. The correlation coefficient of the mathematics subsection of the ACT with erade in the first semester of chemistry a t Xavier (0.477) was roughly equal to that found previously for the SAT mathematics subscore a t the University of Califorrnia-Berkeley (9).This confirms the widely held belief that mathematics sections of aptitudelachieve-
Table 3. Summary ot the Stepwlse Multivariate Linear Rearersion Analvsis Step
Variable Added
Chemistry 1010 1 ACT Composite 2 High School GPA Sex 3 Chemistry 1020 1 Chem I010 Crade 2 High School GPA
R
RaXlOOARaX100
0.547 0.625 0.644
30.0% 39.1% 41.5%
0.671 0.690
45.0% 47.6%
... 9.0% 2.4%
. .. 2.6%
p
