Table 2.

Descriptive Statistics and Zero-Order Correlations among Study Variables

Variable	1	2	3	4	5	6	7	8	9	10	11	Mean (SD) or %	Observed Range
1. Sex (% women)	1	.15	.04	.32**	.33**	.30**	.31**	.19*	−.44**	.11	.33**	63.3%	--
2. PA Group (% yes)		1	.41**	.44**	−.03	.15	.15	.11	−.15	−.09	−.10	50.0%	--
3. ASI-III			1	.53**	−.10	.25*	.21*	.30**	−.18	−.07	−.00	17.65 (13.36)	0 – 66
4. BFI-N				1	.12	.31**	.30**	.26**	−.32**	−.10	.15	24.37 (7.51)	8 – 39
5. Change in SUDS					1	.37**	.38**	.25**	−.40**	.24*	.31**	17.49 (19.07)	−25 – 80
6. DSQ – Total						1	.99**	.85**	−.60**	.30**	.42**	48.99 (29.31)	1 – 119
7. DSQ – Physical							1	.74**	−.61**	.31**	.42**	40.31 (23.28)	1 – 90
8. DSQ – Cognitive								1	−.45**	.22*	.33**	8.68 (7.55)	0 – 32
9. Avoidance Rating									1	−.12	−.32**	47.18 (30.52)	0 – 100
10. Change in SCL										1	.49**	1.63 (1.43)	−.46 – 7
11. Change in HR											1	12.8 (14.70)	−35 – 50

Note:

^*p < .05,

^**p < .01;

Sex (1 = men, 2 = women); PA Group = Panic attack group status [i.e., meets criteria for a past 2-year history of nonclinical, unexpected panic attacks (1 = no, 2 = yes; First et al., 1995); ASI-III = Anxiety Sensitivity Index-III Total Score (Taylor et al., 2007); BFI-N = Big Five Inventory – Neuroticism subscale (John & Srivastava, 1999); Change in SUDS = Difference pre- to post-challenge in Subjective Units of Distress Scale ratings (Wolpe, 1958); DSQ – Total = Diagnostic Sensations Questionnaire – Total mean score; DSQ – Physical = Diagnostic Sensations Questionnaire – Physical symptoms; DSQ – Cognitive = Diagnostic Sensations Questionnaire – Cognitive symptoms (Sanderson et a., 1988, 1989); Avoidance Rating = Self-reported willingness to complete additional CO₂ challenge (0 = not at all willing, 100 = extremely willing; Eifert & Heffner, 2003); Change in SC = Difference pre- to post challenge in Skin Conductance Level; Change in HR = Difference pre- to post-challenge in Heart Rate.