Italics and leading zeros are the formatting details reviewers correct most often. The rules are simple: Latin-letter statistics are italic, Greek letters are not, and the leading zero goes only on values that can be larger than 1. The table below lists the symbols you are most likely to use.
The rules in one place
- Italicize statistical symbols written with Latin letters: M, t, p.
- Do not italicize Greek letters (χ², η², β, α, ε, κ, ω), subscripts that are labels, or abbreviations that are not statistics (CI, ANOVA, SPSS).
- Leading zero: drop it when the value cannot exceed 1 (p, r, R², η², β, α); keep it otherwise (t, F, d, M, b).
- Use the symbol in parentheses and with numbers, and the word in running text: "the mean was higher" but "(M = 4.21)".
The list
| Symbol | Meaning | Italic? | Leading zero? | Example |
|---|---|---|---|---|
| M | Mean | Yes | Yes | M = 4.21 |
| SD | Standard deviation | Yes | Yes | SD = 0.87 |
| SE | Standard error | Yes | Yes | SE = 0.12 |
| Mdn | Median | Yes | Yes | Mdn = 6 |
| n, N | Subsample, total sample | Yes | n/a | N = 120 |
| df | Degrees of freedom | Yes | n/a | df = 58 |
| t | t test statistic | Yes | Yes | t(58) = 2.74 |
| F | F ratio | Yes | Yes | F(2, 87) = 5.83 |
| p | Probability | Yes | No | p = .032 |
| r | Correlation | Yes | No | r(60) = .48 |
| R² | Explained variance | Yes (R) | No | R² = .29 |
| b | Unstandardized coefficient | Yes | Yes | b = 0.42 |
| β | Standardized coefficient | No (Greek) | No | β = .34 |
| χ² | Chi-square | No (Greek) | Yes | χ²(1, N = 200) = 8.14 |
| η², partial η² | Eta squared | No (Greek) | No | partial η² = .14 |
| α | Cronbach's alpha; alpha level | No (Greek) | No | α = .88 |
| κ | Cohen's kappa | No (Greek) | No | κ = .70 |
| d | Cohen's d | Yes | Yes | d = 0.71 |
| U, H, W, z | Mann-Whitney, Kruskal-Wallis, Shapiro-Wilk (or Kendall's W), z | Yes | U, H, z yes; W no | U = 128.50 |
| CI | Confidence interval | No | Follows the statistic | 95% CI [1.70, 10.90] |
Mistakes reviewers catch
- Italic Greek letters: η² or χ².
- Upright Latin symbols: M = 4.21 instead of M = 4.21.
- Leading zeros on p or r: p = 0.032.
- Missing leading zeros on t or d: d = .71.
- Symbols in running text: "the M was higher" should be "the mean was higher".
Let KyroStat do the write-up for you
KyroStat writes every statistic with the right italics and leading zeros, so none of these need fixing by hand.
Frequently asked questions
Is "p" capitalized? No: lowercase italic p.
Do I italicize "ns" for non-significant? Avoid "ns" in text; report the exact p value. See how to report p values.
How do I type χ² and η² in Word? Insert > Symbol for the Greek letter, and superscript for the 2. The Word templates in the APA 7 Manuscript Rescue Vault come with these already set.
What about confidence intervals? See how to report confidence intervals.