Numbers

Use numerals (1, 2, 3, etc.) for the following:

• numbers 10 and above
• numbers used in statistics (e.g., 5.45, 2 x 2 design)
• scores and points on a scale (e.g., 7-point Likert scale)
• exact sums of money (e.g., $5 reward)
• table and figure numbers (e.g., Figure 1, Table 2)

Use words (one, two, three, etc.) for the following:

• numbers zero through nine (e.g., six person groups)
• numbers beginning a sentence, heading, or title (e.g., One-hundred and seventeen participants completed)
• Combine numerals and words to express back-to-back numerical modifiers (e.g., ten 7-point scales, 2 two-way interactions)

Decimals

• Put a zero before the decimal point when a number is less than 1 but the statistic can exceed 1 (e.g., SD = 0.82, Cohen’s d = 0.11)
• Do not use a zero before a decimal when the statistic cannot be greater than 1 (proportion, correlation coefficient, p-value).
• Report 2 decimal places for means, standard deviations, correlations, and inferential statistics (t, F, etc.)

p-values

• If the p-value is greater than .01, report the exact p-value with two decimal places (p = .35)
• If the p-value is between .01 and .001, report the exact p-values with three decimal places (p = .006)
• If the p-value is less than .001, report p < .001

Statistics

• Do not repeat statistics in both the text and a table or figure
• Put a space before and after a mathematical operator (e.g., minus, plus, greater than, less than). For a negative value, put a space only before the minus sign, not after it (e.g., –2.78).
• Use italics for letters used as statistical symbols or algebraic variables.
  • Lower case italic symbols r, t, df, p, Cohen’s d
  • Upper case italic symbols: M, SD, F, R2, N, B, SE
• Use standard (nonitalic) type for Greek letters (e.g., α, β, ω², η², χ²)