APA101 - Answers to Exercises in Lesson 7

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Lesson 7 Exercise

Popular at a Cost: Psychology Students Rate Their Department

Annabelle Scribe
Ivy and Oak University

Psychology graduate students at Ivy and Oak University (IOU) were unhappy. They were paying huge tuition fees, $25,000 a year, and going deeply in debt to attend this prestigious private school, but were unable to find good jobs in their field. The students felt that faculty-course evaluations were biased toward popularity at the expense of competence. Popular professors were promoted: Highly competent but less popular instructors were denied tenure. The faculty was becoming increasingly mediocre as a consequence, devaluing their degrees in the job market. They designed a survey to test this hypothesis.

The survey included questions to measure the competence of the instructor, the demands of the course, and popularity. Also included was an assessment of physical appearance. The grad students hypothesized that instructors that were physically attractive would be more popular. These instructors could "spend" some of that popularity by teaching more demanding courses. One metric of physical appearance is the Body Mass Index (BMI). This index is computed by dividing the weight in kilograms by the square of the person's height in meters. A BMI over 25 is considered overweight: A BMI over 30 qualifies as obese. Stature was measured on a 3-point scale: (short, men under 5 ft 4 in [163 cm], women under 5 ft [152 cm); medium; and (tall, men 6 ft [183 cm] and above, women 5 ft 10 in and above [178 cm]). All other measures were on a 5-point scale. It was also noted whether faculty were tenured, or not.

The survey was sent to all 3rd- and 4th-year students majoring in psychology at IOU. There were 237 surveys returned, with just 9 discarded as unusable. Instructors with high popularity scores (M = 4.5, Mdn = 4, SD = 0.9), rated only average on competence (M = 2.8, Mdn = 2, SD = 1.5). But as expected, instructors rating high in attractiveness (BMI < 25) were both somewhat popular (M = 3.8, Mdn = 4, SD = 1.3), and very competent (M = 4.1, Mdn = 4, SD = 1.2). Just five faculty, 11%, fell into this group. Still, the results were highly significant, t(229) = 2.918, p < .01. Tenured male professors (n = 16) had an average BMI of 32, with an average height of 5 ft 9 in (175 cm), and average body weight of 216 lb (98 kg). There were just three tenured female instructors so results were inconclusive. Nontenured faculty had a BMI = 24.3.

A extensive and elaborate statistical analysis of the data was conducted using SPSS, but the students could make no sense of the data. The statistics requirement for a degree in psychology had been dropped in 1998.

Explanation

The essence of this exercise is that APA rules for presenting numbers and statistics are so complex, with so many exceptions, that it is prudent to study the Manual and adjust your text accordingly. For example, the participants in a study are always represented with numerals, but the observers or raters of the study follow the under 10 rule: there were 6 participants, but five observers.

When is doubt, mostly use numerals, be consistent.

Ivy and Oak University (IOU) The abbreviation is used later in the text but not introduced. The same oversight occurs when Body Mass Index is introduced.
$25,000 Large numbers may be written with a combination of figures words. This number is more familiar as a figure, it is not quite large enough.
kilograms meters. Abbreviations of SI units are only used in the company of numbers (they never end with a period, there is no plural form for SI units abbreviations). Without numbers in the text, units are written out. Follow the same rules when using conventional (non-SI) units.
3-point scale According to the APA Manual (2001), use figures to express "numbers that represent time; dates; ages; sample; subsample; or population size; specific number of subjects or participants in an experiment; scores and points on a scale; exact sums of money; and numerals as numerals" (p. 124).
short The APA Manual (2001) requires the use of italics for the anchors of a scale, in this case: short, medium, tall (p. 100).
5 ft 4 in [163 cm] All precise measures and numbers that precede a unit of measure are presented as figures. APA style allows using conventional units of measure when the instrumentation (tape measure?) is in conventional units. They must be followed by the SI measure in parentheses, or in this case brackets within parentheses.
3rd- and 4th-year Numbers under 10 are to be written as words, unless they express "numbers that represent time; dates; ages; sample; subsample; or population size; specific number of subjects or participants in an experiment; scores and points on a scale; exact sums of money; and numerals as numerals" (p. 124). The specific example of "3rd-year students" is given in the Manual (2001, p. 128).
9 discarded When numbers under 10 are combined with numbers 10 or over they are written as numerals.
(M = 4.5, Mdn = 4, SD = 0.9) Descriptive statistics are placed in parentheses (syntax permitting). APA style has unique abbreviations for some statistics, including Mdn for Median. Decimal fractions under 1 are preceded by a zero unless it is impossible for the value to take a number greater than 1 (e.g., a probability). The mean is presented with differing precision (number of digits) in various measures. Since the numbers are being compared, they must all have the same number of digits (e.g., compare M = 4.5154 with M = 2.8100; but use a more sensible number of digits). If the trailing zeros are dropped from a number it is presumed that it was only computed to the accuracy shown. Put a space before and after arithmetic operators (+ - = <, etc.)
Just five faculty The number of participants in a survey are given with figures, but while the faculty are the subjects of the survey, the students are the participants.
t(229) = 2.918, p < .01. Inferential statistics are presented with the degrees of freedom in parentheses (with the sample size when appropriate). Statistics are placed in italics.
(n = 16) The symbol for the size of a subsample is a lowercase n.
216 lb (98 kg) There is no plural form for SI unit abbreviations; follow the same rule when presenting conventional abbreviations.
three tenured female instructors While the faculty are the focus of the study, the students are the participants. The under 10 rule applies in this case.

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