Chapter 7 Univariate distribution checks

This section reports a series of univariate summary checks of the CRASH-2 dataset.

7.1 Data set overview

Using the Hmisc describe function, we provide an overview of the data set. The descriptive report also provides histograms of continuous variables. For ease of scanning the information, we group the report by measurement type.

7.1.1 Demographic variables

Demographic variables

2 Variables 20207 Observations

age: Age years

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
20203	4	84	0.999	34.56	15.55	18	19	24	30	43	55	64

lowest : 1 14 15 16 17 , highest: 92 94 95 96 99

sex: Sex

n	missing	distinct
20206	1	2

 Value        male female
 Frequency   16935   3271
 Proportion  0.838  0.162

7.1.2 Physiological measurements

Physiological measurements

5 Variables 20207 Observations

sbp: Systolic Blood Pressure mmHg

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
19887	320	173	0.989	98.45	27.86	60	70	80	95	110	130	143

lowest : 4 10 12 20 25 , highest: 225 230 234 240 250

hr: Heart Rate /min

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
20070	137	173	0.996	104.5	23.38	70	80	90	105	120	130	140

lowest : 3 4 5 6 10 , highest: 190 192 198 200 220

rr: Respiratory Rate /min

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
20016	191	68	0.99	23.06	7.052	14	16	20	22	26	30	35

lowest : 1 2 3 4 5 , highest: 90 91 94 95 96

gcs: Glasgow Coma Score Total points

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
20184	23	13	0.863	12.47	3.594	4	6	11	15	15	15	15

lowest : 3 4 5 6 7 , highest: 11 12 13 14 15

 Value          3     4     5     6     7     8     9    10    11    12    13    14
 Frequency    784   520   441   584   733   576   504   663   586   951  1356  2140
 Proportion 0.039 0.026 0.022 0.029 0.036 0.029 0.025 0.033 0.029 0.047 0.067 0.106
                 
 Value         15
 Frequency  10346
 Proportion 0.513

cc: Central Capillary Refille Time s

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
19596	611	20	0.945	3.267	1.67	1	2	2	3	4	5	6

lowest : 1 2 3 4 5 , highest: 17 18 20 30 60

 Value          1     2     3     4     5     6     7     8     9    10    11    12
 Frequency   1510  5328  6020  3367  1805   802   268   271    45   139     3     7
 Proportion 0.077 0.272 0.307 0.172 0.092 0.041 0.014 0.014 0.002 0.007 0.000 0.000
                                                           
 Value         13    15    16    17    18    20    30    60
 Frequency      3    19     3     1     1     2     1     1
 Proportion 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000

7.1.3 Characteristics of injury

Characteristics of injury

2 Variables 20207 Observations

injurytime: Hours Since Injury hours

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
20196	11	93	0.972	2.844	2.35	0.5	1.0	1.0	2.0	4.0	6.0	7.0

lowest : 0.10 0.15 0.20 0.25 0.30 , highest: 22.00 45.00 48.00 72.00 96.00

injurytype: Injury type

n	missing	distinct
20207	0	3

 Value                      blunt           penetrating blunt and penetrating
 Frequency                  11189                  6552                  2466
 Proportion                 0.554                 0.324                 0.122

7.2 Categorical variables

We now provide a closer visual examination of the categorical predictors.

7.2.1 Categorical ordinal plots

The Glasgow coma score, an ordinal categorical variable, is also displayed separately.

7.3 Continuous variables

A closer visual examination of continuous predictors.

There is evidence of digit preference. Explore further with targeted summaries. A more detailed univariate summaries for the variables of interest are also provided below.

7.3.1 Age

## Warning: Removed 2 rows containing missing values (geom_point).

Figure 7.1: Distribution of subject age [years]

Five patients under the age of 17, the inclusion criteria for the study, with one patient aged 1.

7.3.2 Blood pressure

## Warning: Removed 1 rows containing missing values (geom_point).

Figure 7.2: Distribution of SBP

7.3.3 Respiratory rate

Figure 7.3: Distribution of respiratory rate

7.3.4 Heart rate

Figure 7.4: Distribution of heart rate

7.3.5 Central capillary refill time

## Warning: Removed 728 rows containing missing values (geom_point).

Figure 7.5: Distribution of Central capillary refill time

7.3.6 Hours since injury

## Warning: Removed 24 rows containing missing values (geom_point).

Figure 7.6: Distribution of hours since injury

7.4 Section session info

## R version 4.1.3 (2022-03-10)
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