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Table 2 Number of cigarettes smoked per day and measures of smoking behaviour and attitudes (N = 79)

From: Cigarette pack size and consumption: an adaptive randomised controlled trial

 

Packs of ≥25

(n = 39)

Packs of 20

(n = 40)

Mean

(SD)

Mean

(SD)

Mean Difference

(Packs of ≥25 minus Packs of 20)

95% CI

p

Cohen’s d

Number of cigarettes smoked per day

 Primary analysisa

16.8 (6.7)

15.9 (8.5)

−0.9

−4.3, 2.6

0.620

− 0.11

 Secondary analysis*

16.7 (7.7)

15.9 (7.7)

−0.8

−4.3, 2.6

0.639

−0.25

 Per protocol analysis

16.6 (6.7)

16.1 (4.3)

−0.5

−4.2, 3.0

0.766

−0.09

Smoking behaviour and attitudes (post-intervention)**

 HSIb

3.1 (1.1)

2.8 (1.1)

−0.30

− 0.82, 0.23

0.265

− 0.26

 MTSSc

3.8 (1.4)

3.4 (1.4)

−0.46

−1.10, 0.19

0.160

−0.33

 AUTOSd

17.9 (5.2)

17.6 (5.2)

−0.25

−2.67, 2.16

0.838

−0.05

  1. *adjusted for pack size used at baseline, ** adjusted for same measures taken at baseline
  2. aDue to deviations from normality in the primary and secondary outcomes, all analyses were repeated using a bootstrapping method. These produced similar results
  3. bHSI = Heaviness of Smoking Index (range 0–6)
  4. cMTSS = Motivation to Stop Scale (range 1–7)
  5. dAUTOS = Autonomy Over Smoking Scale (range 0–36)