Yeon-jung Choi; Mun-jeong Ju; Jung-hye Park; Jong-hoon Park; Eun-kyung Kim

doi:10.4163/jnh.2017.50.6.552

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Choi, Ju, Park, Park, and Kim: Energy expenditure of physical activity in Korean adults and assessment of accelerometer accuracy by gender∗

Research Article

J Nutr Health 2017;50(6):552-564.

Published online: 20 January 2017

DOI: https://doi.org/10.4163/jnh.2017.50.6.552

Energy expenditure of physical activity in Korean adults and assessment of accelerometer accuracy by gender^∗

Yeon-jung Choi¹, Mun-jeong Ju¹, Jung-hye Park¹, Jong-hoon Park², Eun-kyung Kim^†

¹Department of Food and Nutrition, Gangneung-Wonju National University, Gangneung 25457, Korea

²Department of Physical Education, Korea University, Seoul 02841, Korea

^† To whom correspondence should be addressed. tel: +82-33-640-2336, E-mail: ekkim@gwnu.ac.kr,

^∗ This study was supported by grants from Korea Centers for Disease Control and Prevention (2014-E35002–00).

Received 24 August 2017 Revised 26 September 2017 Accepted 30 November 2017

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

The purpose of this study was to measure energy expenditure (EE) the metabolic equivalents (METs) of 13 common physical activities by using a portable telemetry gas exchange system (K4b²) and to assess the accuracy of the accelerometer (Actigraph GT3X⁺) by gender in Korean adults. Methods: A total of 109 adults (54 males, 55 females) with normal BMI (body mass index) participated in this study. EE and METs of 13 selected activities were simultaneously measured by the K4b² portable indirect calorimeter and predicted by the GT3X⁺ Actigraph accelerometer. The accuracy of the accelerometer was assessed by comparing the predicted with the measured EE and METs. Results: EE (kcal/kg/hr) and METs of treadmill walking (3.2 km/h, 4.8 km/h and 5.6 km/h) and running (6.4 km/h) were significantly higher in female than in male participants (p<0.05). On the other hand, the accelerometer significantly underestimated the EE and METs for all activities except descending stairs, moderate walking, and fast walking in males as well as descending stairs in females. Low intensity activities had the highest rate of accurate classifications (88.3% in males and 91.3% females), whereas vigorous intensity activities had the lowest rate of accurate classifications (43.6% in males and 27.7% in females). Across all activities, the rate of accurate classification was significantly higher in males than in females (75.2% and 58.3% respectively, p<0.01). Error between the accelerometer and K4b² was smaller in males than in females, and EE and METs were more accurately estimated during treadmill activities than other activities in both males and females. Conclusion: The accelerometer underestimated EE and METs across various activities in Korean adults. In addition, there appears to be a gender difference in the rate of accurate accelerometer classification of activities according to intensity. Our results indicate the need to develop new accelerometer equations for this population, and gender differences should be considered.

Keywords: estimated energy requirements, physical activity, physical intensity, indirect calorimetry, accelerometer

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Fig 1.

Agreement rate of physical activity intensity classifications between K4b² and accelerometer measurements in male and female. Activity intensity classification was described using agreement rate of physical activity intensity classification and Kappa statistics was used to describe the level of agreement rate between K4b² and accelerometer.

Table 1.

Description of 13 physical activities investigated

Intensity¹⁾	METs²⁾	Activity	Description
Basic		Lying	Lying on bed
Light	1 ∼ 2	Sitting	Sitting in an arm chair quietly
		Standing	Standing without moving and speaking
		Washing dishes	Washing different size dishes
		Slow walking	Walking on a treadmill at 3.2 km/h
		Vacuuming	Vacuuming a room (about 22m²) at a self selected speed
Moderate	3 ∼ 5	Moderate walking	Walking on a treadmill at 4.8 km/h
		Descending stairs	Going down the stairs from the 10^th floor to the 1^st floor at a self selected speed
		Fast walking	Walking on a treadmill at 5.6 km/h
		Moving a box	Moving a 2.5 kg box from left to right without movement of legs
Vigorous	6 ∼	Slow running	Running on a treadmill at 6.4 km/h
		Ascending stairs	Going up the stairs to the 10^th floor at a self selected speed
		Moderate running	Running on a treadmill at 8 km/h

¹⁾ Classification of physical activity intensity by Compendium 2011²⁰ 2) METs: metabolic equivalents

Table 2.

Anthropometric measurements of the subjects

	Male	Female	Total
	(n = 54)	(n = 55)	(n = 109)
Age (years)	40.8 ± 12.7¹⁾	40.2 ± 12.9	40.5 ± 12.8
Height (cm)	171.0 ± 5.4^∗∗	157.8 ± 5.0	164.4 ± 8.4
Body weight (kg)	71.1 ± 9.2^∗∗	56.7 ± 8.3	63.8 ± 11.3
Body mass index (kg/m²)	24.3 ± 2.6^∗	22.7 ± 2.9	23.5 ± 2.8
Body fat (%)²⁾	22.5 ± 5.7	31.6 ± 5.4^∗∗	27.1 ± 7.2

¹⁾ Mean ± SD 2) Measured by Inbody 720 Significant difference between male and female was tested by independent t-test.

^∗ p < 0.01,

^∗∗ p < 0.001

Table 3.

Oxygen consumption, carbon dioxide production, energy expenditure and METs measured by K4b²

Activities	2) (L/kg/hr) VO₂		VCO₂ 3) (L/kg/hr)		Energy Ex.⁴⁾ (kcal/kg/hr)				METs⁵⁾
Activities	Male	Female	Male	Female	Male	Female	Total	Male	Female	Total
Lying	0.22 ± 0.02¹⁾	0.24 ± 0.03∗	0.19 ± 0.0.2	0.21 ± 0.03∗	1.06 ± 0.11	1.18 ± 0.17^∗	1.12 ± 0.15^6)a	1.03 ± 0.11	1.16 ± 0.16^∗	1.10 ± 0.15^a
Sitting	0.25 ± 0.03	0.26 ± 0.04	0.21 ± 0.03	0.22 ± 0.04	1.19 ± 0.17	1.25 ± 0.20	1.22 ± 0.19^a	1.18 ± 0.16	1.23 ± 0.20	1.20 ± 0.18^a
Standing	0.24 ± 0.06	0.25 ± 0.05	0.20 ± 0.05	0.21 ± 0.04	1.14 ± 0.27	1.20 ± 0.22	1.17 ± 0.25^a	1.13 ± .26	1.18 ± 0.23	1.16 ± 0.25^a
Washing dishes	0.48 ± 0.08	0.49 ± 0.09	0.38 ± 0.07	0.39 ± 0.08	2.26 ± 0.40	2.34 ± 0.45	2.30 ± 0.42^b	2.26 ± 0.40	2.35 ± 0.45	2.30 ± 0.42^b
Moving boxes	0.55 ± 0.12	0.58 ± 0.14	0.46 ± 0.11	0.48 ± 0.12	2.62 ± .57	2.80 ± 0.67	2.71 ± 0.63^c	2.59 ± 0.56	2.78 ± 0.66	2.69 ± 0.62^c
Vacuuming	0.57 ± 0.11	0.67 ± 0.16^∗∗∗	0.46 ± 0.10	0.54 ± 0.13^∗∗	2.71 ± 0.55	3.20 ± 0.75^∗∗∗	2.96 ± 0.70^c	2.69 ± 0.54	3.20 ± 0.75^∗∗∗	2.95 ± 0.70^c
Slow walking at 3.2 km/h	0.62 ± 0.10	0.71 ± 0.13^∗∗∗	0.51 ± 0.10	0.58 ± 0.13^∗∗	2.96 ± 0.50	3.40 ± 0.66^∗∗∗	3.18 ± 0.62^a	2.93 ± 0.48	3.38 ± 0.64^∗∗∗	3.15 ± 0.61^a
Descending stairs	0.68 ± 0.14	0.72 ± 0.15	0.60 ± 0.11	0.59 ± 0.11	3.31 ± 0.67	3.45 ± 0.70	3.38 ± 0.69^a	3.24 ± 0.68	3.43 ± 0.73	3.34 ± 0.71^a
Moderate walking at 4.8 km/h	0.81 ± 0.11	0.97 ± 0.16^∗∗∗	0.69 ± 0.10	0.81 ± 0.16^∗∗∗	3.91 ± 0.54	4.66 ± 0.79^∗∗∗	4.29 ± 0.77^b	3.86 ± 0.53	4.60 ± 0.76^∗∗∗	4.23 ± 0.75^b
Fast walking at 5.6 km/h	1.01 ± 0.16	1.18 ± 0.19^∗∗∗	0.88 ± 0.16	1.04 ± 0.21^∗∗∗	4.89 ± 0.79	5.75 ± 0.97^∗∗∗	5.32 ± 0.98^c	4.79 ± 0.75	5.62 ± 0.91^∗∗∗	5.21 ± 0.93^c
Slow running at 6.4 km/h	1.34 ± 0.21	1.50 ± 0.18^∗∗∗	1.24 ± 0.23	1.38 ± 0.21^∗∗	6.60 ± 1.06	7.36 ± 0.91^∗∗∗	6.99 ± 1.05^a	6.39 ± 0.99	7.12 ± 0.85^∗∗∗	6.76 ± 0.99^a
Ascending stairs	1.78 ± 0.24	1.71 ± 0.23	1.67 ± 0.20	1.74 ± 0.25	8.78 ± 1.08	8.61 ± 1.10	8.70 ± 1.09^b	8.47 ± 1.12	8.15 ± 1.10	8.31 ± 1.12^b
Moderate running at 8 km/h	1.73 ± 0.20	1.77 ± 0.19	1.65 ± 0.19	1.76 ± 0.20^∗∗	8.57 ± 0.97	8.86 ± 0.90	8.71 ± 0.94^b	8.22 ± 0.95	8.42 ± 0.89	8.32 ± 0.92^b
Total	0.78 ± 0.53	0.84 ± 0.53^∗	0.70 ± 0.51	0.75 ± 0.54	4.15 ± 2.58	4.45 ± 2.61^∗	4.30 ± 2.60	4.05 ± 2.47	4.34 ± 2.46^∗	4.19 ± 2.47

¹⁾ Mean ± SD 2) VO₂: oxygen consumption 3) VCO₂: carbon dioxide production 4) Energy Ex.: energy expenditure 5) METs: metabolic equivalents 6) abc: Means with same superscripts are not significantly different at p < 0.05 by Tamhane's multiple comparison test (Light, Moderate activities) and Scheffe's multiple comparison test (Vigorous activites) by intensity (Light < 3METs, 3METs ≤ Moderate < 6METs, 6METs ≤ Vigorous). Significantly different between male and female by independent t-test at

^∗ p < 0.05,

^∗∗ p < 0.01 and

^∗∗∗ p < 0.001

Table 4.

Comparison of energy expenditure, METs and intensity for all activities measured by K4b² and estimated by equations using Actigraph

Activities		Energy expenditure (kcal/kg/hr)				METs²⁾				Intensity³⁾
	Male		Female		Male		Female		Male		Female
	K4b²	Actigraph⁴⁾	K4b²	Actigraph	K4b²	Actigraph⁵⁾	K4b²	Actigraph	K4b² A	Actigraph	h K4b² A	Actigraph
Lying	1.06 ± 0.11^1)∗∗∗	0.00 ± 0.00	1.18 ± 0.17^∗∗∗	0.00 ± 0.00	1.03 ± 0.11^∗∗∗	1.00 ± 0.00	1.16 ± .0.16^∗∗∗	1.00 ± 0.00	L	L	L	L
Sitting	1.19 ± 0.17^∗∗∗	0.00 ± 0.00	1.25 ± 0.20^∗∗∗	0.00 ± 0.00	1.18 ± 0.16^∗	1.00 ± 0.00	1.23 ± 0.20^∗∗∗	1.00 ± 0.00	L	L	L	L
Standing	1.14 ± 0.27^∗∗∗	0.00 ± 0.00	1.20 ± 0.22^∗∗∗	0.00 ± 0.00	1.13 ± 0.26^∗∗	1.00 ± 0.00	1.18 ± 0.23^∗∗∗	1.00 ± 0.00	L	L	L	L
Washing dishes	2.26 ± 0.40^∗∗∗	0.02 ± 0.05	2.34 ± 0.45^∗∗∗	0.02 ± 0.08	2.26 ± 0.40^∗∗∗	1.00 ± 0.00	2.35 ± 0.45^∗∗∗	1.00 ± 0.02	L	L	L	L
Moving boxes	2.62 ± 0.57^∗∗∗	0.04 ± 0.08	2.80 ± 0.67^∗∗∗	0.11 ± 0.47	2.59 ± 0.56^∗∗∗	1.00 ± 0.01	2.78 ± 0.66^∗∗∗	1.05 ± 0.32	L	L	L	L
Vacuuming	2.71 ± 0.55^∗∗∗	0.22 ± 0.29	3.20 ± 0.75^∗∗∗	0.22 ± 0.51	2.69 ± 0.54^∗∗∗	1.06 ± 0.13	3.20 ± 0.75^∗∗∗	1.07 ± 0.35	L	L	M	L
Slow walking at 3.2 km/h	2.96 ± 0.50^∗∗∗	1.14 ± 0.47	3.40 ± 0.66^∗∗∗	1.01 ± 0.49	2.93 ± 0.48^∗∗∗	1.28 ± 0.29	3.38 ± 0.64^∗∗∗	1.21 ± 0.30	L	L	M	L
Descending stairs	3.31 ± 0.67	4.70 ± 1.08^∗∗∗	3.45 ± 0.70	3.60 ± 1.03	3.24 ± 0.68	4.70 ± 1.08^∗∗∗	3.43 ± 0.73	3.58 ± 1.04	M	M	M	M
Moderate walking at 4.8 km/h	3.91 ± 0.54	3.91 ± 0.95	4.66 ± 0.79^∗∗∗	2.98 ± 1.06	3.86 ± 0.53	3.92 ± 0.94	4.60 ± 0.76^∗∗∗	2.97 ± 1.06	M	M	M	L
Fast walking at 5.6 km/h	4.89 ± 0.79	4.90 ± 0.73	5.76 ± 0.97^∗∗∗	3.81 ± 1.15	4.79 ± 0.75	4.89 ± 0.73	5.64 ± 0.92^∗∗∗	3.77 ± 1.17	M	M	M	M
Slow running at 6.4 km/h	6.60 ± 1.06^∗∗	5.88 ± 1.22	7.36 ± 0.91^∗∗∗	4.89 ± 1.41	6.39 ± 0.99^∗	5.86 ± 1.21	7.12 ± 0.85^∗∗∗	4.86 ± 1.40	V	M	V	M
Ascending stairs	8.78 ± 1.08^∗∗∗	3.97 ± 1.10	8.61 ± 1.10^∗∗∗	2.72 ± 0.79	8.47 ± 1.12^∗∗∗	3.98 ± 1.09	8.15 ± 1.10^∗∗∗	2.69 ± 0.76	V	M	V	L
Moderate running at 8 km/h	8.57 ± 0.97^∗∗∗	7.11 ± 1.27	8.86 ± 0.90^∗∗∗	6.42 ± 1.29	8.22 ± 0.95^∗∗∗	7.08 ± 1.27	8.42 ± 0.89^∗∗∗	6.36 ± 1.29	V	V	V	V

¹⁾ Mean ± SD 2) METs: metabolic equivalent 3) Classified by Compendium 2011 (L: Light < 3METs, 3METs ≤ M: Moderate < 6METs, 6METs ≤ V: Vigorous) 4) calculated from Freedson combination equation 5) calculated from Freedson adult (1998) Significantly different between K4b

² and Actigraph by independent t-test at

^∗ p < 0.05,

^∗∗ p < 0.01 and

^∗∗∗ p < 0.001

Table 5.

Accuracy of Actigraph for energy expenditure measurement by gender

Activities	Difference2) (kcal/kg/hr)		Bias3) (%)		RMSE4)		Predictions (%)
Activities	Difference2) (kcal/kg/hr)		Bias3) (%)		RMSE4)		Accurate⁵⁾		Under⁶⁾		Over⁷⁾
	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female
Lying	–1.11 ± 0.16	–1.21 ± 0.20^∗∗	–99.99 ± 0.10	–99.96 ± 0.16	1.12	1.23	0	0	100	100	0	0
Sitting	–1.06 ± 0.17	–1.15 ± 0.22^∗	–99.97 ± 0.21	–99.97 ± 0.15	1.07	1.17	0	0	100	100	0	0
Standing	–1.14 ± 0.27	–1.20 ± 0.22	–100.00 ± 0.00	–100.00 ± 0.00	1.17	1.22	0	0	100	100	0	0
Washing dishes	–2.24 ± 0.40	–2.32 ± 0.47	–98.99 ± 2.37	–98.95 ± 4.62	2.28	2.37	0	0	100	100	0	0
Moving boxes	–2.59 ± 0.55	–2.69 ± 0.81	–98.78 ± 2.40	–96.26 ± 16.38	2.64	2.81	0	0	100	98.2	0	1.8
Vacuuming	–2.49 ± 0.44	–2.98 ± 0.85^∗∗∗	–92.75 ± 7.91	–93.23 ± 16.16	2.53	3.10	0	0	100	98.2	0	1.8
Slow walking at 3.2 km/h	–1.82 ± 0.80	–2.39 ± 0.87^∗∗	–59.70 ± 18.79	–68.68 ± 17.46^∗	1.98	2.54	0	0	100	100	0	0
Descending stairs	1.39 ± 1.45^∗∗∗	0.15 ± 1.48	49.04 ± 47.70^∗∗	13.56 ± 59.90	1.99	1.47	3.7	12.7	11.1	43.6	85.2	43.6
Moderate walking at 4.8 km/h	0.00 ± 1.28	–1.68 ± 1.43^∗∗∗	2.69 ± 29.89	–33.50 ± 28.60^∗∗∗	1.27	2.20	25.9	7.3	29.6	83.6	44.4	9.1
Fast walking at 5.6 km/h	0.01 ± 1.17	–1.95 ± 1.57^∗∗∗	2.79 ± 22.29	–31.80 ± 24.66^∗∗∗	1.16	4.93	29.6	13.0	31.5	81.5	38.9	5.6
Slow running at 6.4 km/h	–0.72 ± 1.46	–2.47 ± 1.61^∗∗∗	–9.18 ± 20.22	–32.71 ± 20.56^∗∗∗	1.62	2.94	40.4	13.0	42.3	85.2	17.3	1.9
Ascending stairs	–4.82 ± 1.58	–5.89 ± 1.27^∗∗∗	–54.11 ± 13.72	–68.00 ± 9.52^∗∗∗	5.06	6.02	0	0	100	100	0	0
Moderate running at 8 km/h	–1.46 ± 1.55	–2.44 ± 1.62^∗∗	–16.14 ± 16.60	–26.74 ± 16.85^∗∗	2.12	2.92	32.0	17.4	62.0	82.6	6.0	0
Across all activities	–1.39 ± 1.78¹⁾	–2.17 ± 1.74^∗∗∗	–52.07 ± 53.67	–64.89 ± 42.99^∗∗∗	2.25	2.78	10.0	4.7	75.2	90.3	14.9	5.0
Treadmill activities	–0.79 ± 1.47	–2.18 ± 1.46^∗∗∗	–15.96 ± 32.05	–39.03 ± 26.85^∗∗∗	1.66	2.62	25.4	9.9	53.0	86.7	21.6	3.4

¹⁾ Mean ± SD 2) Difference = predicted by Actigraph – measured by K4b

³⁾ Bias: mean percentage error between Actigraph and K4b

⁴⁾ RMSE: root mean squared error 5) The percentage of subjects predicted by Actigraph within 10% of EE measured by K4b

⁶⁾ The percentage of subjects predicted by Actigraph < 10% of EE measured by K4b

⁷⁾ The percentage of subjects predicted by Actigraph > 10% of EE measured by K4b² Significantly different between K4b² and Actigraph by independent t-test at

^∗ p < 0.05,

^∗∗ p < 0.01 and

^∗∗∗ p < 0.001

Table 6.

Accuracy of Actigraph for METs by gender

Activities	Difference2) (METs)		Bias3) (%)		RMSE4)				Predictions (%)
	Difference2) (METs)		Bias3) (%)		RMSE4)		Accurate⁵⁾		Under⁶⁾		Over⁷⁾
	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female	Male	Female
Lying	–0.08 ± 0.16²⁾	–0.19 ± 0.20^∗∗	–5.99 ± 12.72	–13.83 ± 13.93^∗∗	0.18	0.27	51.9	34.5	37.0	60.0	11.1	5.5
Sitting	–0.05 ± 0.17	–0.14 ± 0.22^∗	–2.18 ± 15.43	–8.95 ± 17.18^∗	0.17	0.26	38.9	34.5	38.9	50.9	22.2	14.5
Standing	–0.13 ± 0.26	–0.18 ± 0.23	–8.04 ± 16.03	–12.53 ± 16.41	0.29	0.29	51.9	30.9	35.2	60.0	13.0	9.1
Washing dishes	–1.26 ± 0.40	–1.34 ± 0.45	–54.46 ± 7.60	–55.44 ± 9.86	1.32	1.41	0	0	100	100	0	0
Moving boxes	–1.59 ± 0.55	–1.73 ± 0.72	–59.81 ± 7.71	–60.29 ± 13.77	1.68	1.87	0	0	100	98.2	0	1.8
Vacuuming	–1.63 ± 0.49	–2.14 ± 0.82^∗∗∗	–59.44 ± 7.15	–64.95 ± 13.29^∗∗	1.70	2.29	0	1.8	100	98.2	0	0
Slow walking at 3.2 km/h	–1.65 ± 0.64	–2.17 ± 0.75^∗∗∗	–54.87 ± 13.87	–62.61 ± 12.85^∗∗	1.76	2.29	0	0	100	100	0	0
Descending stairs	1.46 ± 1.46^∗∗∗	0.14 ± 1.52	52.95 ± 49.77^∗∗	13.95 ± 61.27	2.05	1.52	1.9	10.9	11.1	43.6	87.0	45.5
Moderate walking at 4.8 km/h	0.06 ± 1.26	–1.64 ± 1.40^∗∗∗	4.29 ± 30.01	–33.07 ± 28.76^∗∗∗	1.25	2.15	20.4	9.1	29.6	81.8	50.0	9.1
Fast walking at 5.6 km/h	0.11 ± 1.14	–1.87 ± 1.57^∗∗∗	4.82 ± 22.37	–31.09 ± 25.30^∗∗∗	1.13	2.43	31.5	11.1	29.6	83.3	38.9	5.6
Slow running at 6.4 km/h	–0.53 ± 1.42	–2.26 ± 1.60^∗∗∗	–6.55 ± 20.53	–30.92 ± 21.20^∗∗∗	1.50	2.76	42.3	16.7	36.5	81.5	21.2	1.9
Ascending stairs	–4.49 ± 1.59	–5.46 ± 1.27^∗∗	–52.18 ± 14.37	–66.48 ± 9.95^∗∗∗	4.76	5.60	1.9	0	98.1	100	0	0
Moderate running at 8 km/h	–1.14 ± 1.54	–2.06 ± 1.61^∗∗	–12.90 ± 17.31	–23.59 ± 17.76^∗∗	1.90	2.61	30.0	19.6	56.0	76.1	14.0	4.3
Across all activities	–0.84 ± 1.70¹⁾	–1.61 ± 1.77^∗∗∗	–19.47 ± 39.08	–34.71 ± 34.42^∗∗∗	1.89	2.40	20.8	12.9	59.3	79.5	19.9	7.5
Treadmill activities	–0.62 ± 1.40	–2.00 ± 1.43^∗∗∗	–13.09 ± 30.88	–36.63 ± 25.75^∗∗∗	1.53	2.45	24.6	11.0	50.4	84.8	25.0	4.2

¹⁾ Mean ± SD

²⁾ Difference = predicted by Actigraph – measured by K4b

³ Bias: mean percentage error between Actigraph and K4b

⁴ RMSE: root mean squared error

⁵ The percentage of subjects predicted by Actigraph within 10% of EE measured by K4b

⁶ The percentage of subjects predicted by Actigraph < 10% of EE measured by K4b

⁷ The percentage of subjects predicted by Actigraph > 10% of EE measured by K4b² Significantly different between K4b² and Actigraph by independent t-test at

^∗ p < 0.05,

^∗∗ p < 0.01 and

^∗∗∗ p < 0.001

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