| title | author | date | output | ||||
|---|---|---|---|---|---|---|---|
Codebook |
Eugene Terblanche |
2015-10-19 |
|
This project creates a subset of the training and testing data that was recorded from the experiment to record activity data for 30 subjects. The Signal data was ignored as the project only requires that the measured data should be cleaned and presented.
##Study design and data processing
###Collection of the raw data The initial raw data was collected from the Accelerometer and gyroscope from subjects (19-48 years) wearing a smartphone (samsung Galaxy SII). Each person performed the following activities:
- Walking.
- Walking a flight od stairs.
- Walking down a flight of stairs.
- Sitting stationary
- Laying down
The dataset created by this project is a combination (merged) set of the testing and the training data.
###Notes on the original (raw) data The original data sample was grouped in a training (70%) and a test set (30%). The orginal Signal data is omitted for this project as we are only interested in the measured data.
##Creating the tidy datafile
###Guide to create the tidy data file The following steps were completed (The ReadMe file also provide HowTo information):
- The data set was downloaded from the link provided. The data was extracted to a newly created Project Directory.
- R Studio was used to create a Project and an R script in this directory. The working directory was set to the project directory. Please se the Notes regarding the OS(Linux) this was tested on.
- An R file to extract and tidy the data was created and named "run_analysis.R"
- Running the run_analysis completes STEP 1 - STEP 5 as per the project requirement.
- The script merges, and cleans the data and writes the data to a new file - "avg_tidydata.txt"
###Cleaning of the data
- The script start by setting the Data directory to where the data was extracted.
- The libraries used in this script to tidy the data are loaded (dplyr)
- The training dataset is then created by reading the "X_train.txt" and the "features" table is used as the column names. The Readme file was here used that states that each column is the "X_train.txt" corresponds to a variable as in the featues table.
- The training activity table was created by reading the "y_train.txt" file. According to the ReadMe file from the original dataset this is the Activity for each measurement in the "X_train.txt" file. The column name was changed to activity.
- The "features.txt" file is loaded in a dataset(features) - This produces a table with a list of all the variables.
- STEP -1 from the requirements is then performed, the training and the testing data is merged (rbind() function was used) The labels from the training and testing datasets is also merged as welll as the subjects dataset.
- The features dataset is now used to apply to the column names of the merged dataset. The subjects and the labels datasets is given new column (variable names).
- The variables that has mean or std in their description and is extracted, this is now used in sub setting only the variables to be used from the merged dataset. STEP -2.
- The activity values were replaced by the Activity Labels: ('Walking','Walking up stairs', 'Walking down stairs', 'Sitting', 'Standing', 'Laying') in the activity dataset. STEP -3.
- The variables is then renamed for the merged dataset. STEP -4.
- STEP 5 from the project requirement is then completed by averaging each variable and writing the result to a text file. "avg_tidydata.txt"
##Description of the variables in the "avg_tidydata.txt" file
General description of the file including:
- Dimensions: 83 variables and 35 observations
- Summary of the data
activity subject TimedomainBodyAccelerationmeanX TimedomainBodyAccelerationmeanY
LAYING :6 Min. : 1.00 Min. :0.2423 Min. :-0.03166
SITTING :6 1st Qu.: 8.50 1st Qu.:0.2727 1st Qu.:-0.01896
STANDING :7 Median :16.00 Median :0.2759 Median :-0.01768
WALKING :6 Mean :15.71 Mean :0.2736 Mean :-0.01815
WALKING_DOWNSTAIRS:4 3rd Qu.:22.50 3rd Qu.:0.2771 3rd Qu.:-0.01692
WALKING_UPSTAIRS :6 Max. :30.00 Max. :0.2792 Max. :-0.01445
TimedomainBodyAccelerationmeanZ TimedomainGravityAccelerationmeanX TimedomainGravityAccelerationmeanY
Min. :-0.1183 Min. :0.4412 Min. :-0.350769
1st Qu.:-0.1109 1st Qu.:0.6464 1st Qu.:-0.067810
Median :-0.1088 Median :0.6813 Median : 0.002085
Mean :-0.1090 Mean :0.6751 Mean :-0.010878
3rd Qu.:-0.1074 3rd Qu.:0.7037 3rd Qu.: 0.066294
Max. :-0.1010 Max. :0.9084 Max. : 0.200569
TimedomainGravityAccelerationmeanZ TimedomainBodyAccelerationJerkmeanX TimedomainBodyAccelerationJerkmeanY
Min. :-0.27820 Min. :0.06861 Min. :-0.001372
1st Qu.: 0.03295 1st Qu.:0.07727 1st Qu.: 0.004524
Median : 0.06232 Median :0.07886 Median : 0.007304
Mean : 0.06841 Mean :0.07967 Mean : 0.008614
3rd Qu.: 0.14069 3rd Qu.:0.08182 3rd Qu.: 0.012233
Max. : 0.26623 Max. :0.10590 Max. : 0.032078
TimedomainBodyAccelerationJerkmeanZ TimedomainBodyAngularSpeedmeanX TimedomainBodyAngularSpeedmeanY
Min. :-0.032698 Min. :-0.07353 Min. :-0.17216
1st Qu.:-0.007646 1st Qu.:-0.04753 1st Qu.:-0.08332
Median :-0.003553 Median :-0.02576 Median :-0.07444
Mean :-0.005631 Mean :-0.02715 Mean :-0.07671
3rd Qu.:-0.001159 3rd Qu.:-0.01903 3rd Qu.:-0.06699
Max. : 0.003645 Max. : 0.11961 Max. :-0.04514
TimedomainBodyAngularSpeedmeanZ TimedomainBodyAngularAccelerationmeanX
Min. :-0.004648 Min. :-0.11905
1st Qu.: 0.084701 1st Qu.:-0.10546
Median : 0.087284 Median :-0.09881
Mean : 0.085932 Mean :-0.09759
3rd Qu.: 0.096384 3rd Qu.:-0.08973
Max. : 0.109093 Max. :-0.07311
TimedomainBodyAngularAccelerationmeanY TimedomainBodyAngularAccelerationmeanZ
Min. :-0.05938 Min. :-0.07434
1st Qu.:-0.04415 1st Qu.:-0.05763
Median :-0.04176 Median :-0.05558
Mean :-0.04284 Mean :-0.05560
3rd Qu.:-0.04012 3rd Qu.:-0.05307
Max. :-0.03688 Max. :-0.04507
TimedomainBodyAccelerationMagnitudemean TimedomainGravityAccelerationMagnitudemean
Min. :-0.9854 Min. :-0.9854
1st Qu.:-0.6085 1st Qu.:-0.6085
Median :-0.5428 Median :-0.5428
Mean :-0.5419 Mean :-0.5419
3rd Qu.:-0.5143 3rd Qu.:-0.5143
Max. : 0.1946 Max. : 0.1946
TimedomainBodyAccelerationJerkMagnitudemean TimedomainBodyAngularSpeedMagnitudemean
Min. :-0.99325 Min. :-0.9833
1st Qu.:-0.70263 1st Qu.:-0.6785
Median :-0.65018 Median :-0.6177
Mean :-0.64090 Mean :-0.6016
3rd Qu.:-0.59914 3rd Qu.:-0.5492
Max. :-0.06621 Max. :-0.1373
TimedomainBodyAngularAccelerationMagnitudemean FrequencydomainBodyAccelerationmeanX
Min. :-0.9943 Min. :-0.99450
1st Qu.:-0.8134 1st Qu.:-0.68461
Median :-0.7859 Median :-0.61952
Mean :-0.7614 Mean :-0.61688
3rd Qu.:-0.7040 3rd Qu.:-0.57958
Max. :-0.5439 Max. :-0.04146
FrequencydomainBodyAccelerationmeanY FrequencydomainBodyAccelerationmeanZ
Min. :-0.9824 Min. :-0.9865
1st Qu.:-0.6051 1st Qu.:-0.7326
Median :-0.5485 Median :-0.6843
Mean :-0.5290 Mean :-0.6631
3rd Qu.:-0.4744 3rd Qu.:-0.6299
Max. : 0.1231 Max. :-0.1986
FrequencydomainBodyAccelerationmeanFreqX FrequencydomainBodyAccelerationmeanFreqY
Min. :-0.31917 Min. :-0.15308
1st Qu.:-0.23726 1st Qu.:-0.02263
Median :-0.21243 Median : 0.03604
Mean :-0.20959 Mean : 0.02073
3rd Qu.:-0.18413 3rd Qu.: 0.07263
Max. :-0.02094 Max. : 0.12808
FrequencydomainBodyAccelerationmeanFreqZ FrequencydomainBodyAccelerationJerkmeanX
Min. :-0.10784 Min. :-0.994117
1st Qu.: 0.00420 1st Qu.:-0.715484
Median : 0.05028 Median :-0.652023
Mean : 0.05474 Mean :-0.646034
3rd Qu.: 0.08813 3rd Qu.:-0.611146
Max. : 0.28697 Max. : 0.007745
FrequencydomainBodyAccelerationJerkmeanY FrequencydomainBodyAccelerationJerkmeanZ
Min. :-0.9888 Min. :-0.9906
1st Qu.:-0.6956 1st Qu.:-0.7955
Median :-0.6294 Median :-0.7656
Mean :-0.6189 Mean :-0.7413
3rd Qu.:-0.5871 3rd Qu.:-0.7069
Max. :-0.0429 Max. :-0.3882
FrequencydomainBodyAccelerationJerkmeanFreqX FrequencydomainBodyAccelerationJerkmeanFreqY
Min. :-0.219176 Min. :-0.3478
1st Qu.:-0.095135 1st Qu.:-0.2476
Median :-0.038915 Median :-0.2068
Mean :-0.030002 Mean :-0.2010
3rd Qu.: 0.006708 3rd Qu.:-0.1654
Max. : 0.263820 Max. : 0.1082
FrequencydomainBodyAccelerationJerkmeanFreqZ FrequencydomainBodyAngularSpeedmeanX
Min. :-0.29029 Min. :-0.9860
1st Qu.:-0.16960 1st Qu.:-0.7058
Median :-0.11253 Median :-0.6674
Mean :-0.11225 Mean :-0.6666
3rd Qu.:-0.07941 3rd Qu.:-0.6387
Max. : 0.12948 Max. :-0.2371
FrequencydomainBodyAngularSpeedmeanY FrequencydomainBodyAngularSpeedmeanZ
Min. :-0.9874 Min. :-0.9887
1st Qu.:-0.7861 1st Qu.:-0.7095
Median :-0.7448 Median :-0.6707
Mean :-0.7069 Mean :-0.6384
3rd Qu.:-0.6302 3rd Qu.:-0.6021
Max. :-0.4771 Max. :-0.1585
FrequencydomainBodyAngularSpeedmeanFreqX FrequencydomainBodyAngularSpeedmeanFreqY
Min. :-0.24134 Min. :-0.37533
1st Qu.:-0.14058 1st Qu.:-0.23151
Median :-0.10257 Median :-0.16665
Mean :-0.10014 Mean :-0.16657
3rd Qu.:-0.04414 3rd Qu.:-0.09676
Max. : 0.02891 Max. : 0.07375
FrequencydomainBodyAngularSpeedmeanFreqZ FrequencydomainBodyAccelerationMagnitudemean
Min. :-0.212818 Min. :-0.99001
1st Qu.:-0.088672 1st Qu.:-0.65311
Median :-0.048165 Median :-0.58993
Mean :-0.046889 Mean :-0.58148
3rd Qu.:-0.001057 3rd Qu.:-0.52877
Max. : 0.101045 Max. :-0.02958
FrequencydomainBodyAccelerationMagnitudemeanFrequency FrequencydomainBodyBodyAccelerationJerkMagnitudemean
Min. :-0.06007 Min. :-0.993006
1st Qu.: 0.03975 1st Qu.:-0.684158
Median : 0.08732 Median :-0.614818
Mean : 0.09261 Mean :-0.611856
3rd Qu.: 0.13274 3rd Qu.:-0.568708
Max. : 0.32008 Max. : 0.003827
FrequencydomainBodyBodyAccelerationJerkMagnitudemeanFrequency
Min. :0.0817
1st Qu.:0.1401
Median :0.1829
Mean :0.1823
3rd Qu.:0.2132
Max. :0.4287
FrequencydomainBodyBodyAngularSpeedMagnitudemean FrequencydomainBodyBodyAngularSpeedMagnitudemeanFrequency
Min. :-0.9866 Min. :-0.22082
1st Qu.:-0.7566 1st Qu.:-0.10931
Median :-0.7173 Median :-0.03615
Mean :-0.6956 Mean :-0.04249
3rd Qu.:-0.6326 3rd Qu.: 0.00961
Max. :-0.3544 Max. : 0.15472
FrequencydomainBodyBodyAngularAccelerationMagnitudemean
Min. :-0.9933
1st Qu.:-0.8382
Median :-0.8101
Mean :-0.7813
3rd Qu.:-0.7148
Max. :-0.5841
FrequencydomainBodyBodyAngularAccelerationMagnitudemeanFrequency TimedomainBodyAccelerationstdX
Min. :-0.01339 Min. :-0.99504
1st Qu.: 0.07620 1st Qu.:-0.66457
Median : 0.14588 Median :-0.60559
Mean : 0.13554 Mean :-0.60130
3rd Qu.: 0.19563 3rd Qu.:-0.57448
Max. : 0.37006 Max. : 0.07648
TimedomainBodyAccelerationstdY TimedomainBodyAccelerationstdZ TimedomainGravityAccelerationstdX
Min. :-0.9794 Min. :-0.98098 Min. :-0.9933
1st Qu.:-0.5792 1st Qu.:-0.69785 1st Qu.:-0.9732
Median :-0.5314 Median :-0.64710 Median :-0.9665
Mean :-0.5024 Mean :-0.61266 Mean :-0.9653
3rd Qu.:-0.4389 3rd Qu.:-0.55494 3rd Qu.:-0.9594
Max. : 0.2200 Max. :-0.09352 Max. :-0.9397
TimedomainGravityAccelerationstdY TimedomainGravityAccelerationstdZ TimedomainBodyAccelerationJerkstdX
Min. :-0.9848 Min. :-0.9813 Min. :-0.9940
1st Qu.:-0.9604 1st Qu.:-0.9502 1st Qu.:-0.7002
Median :-0.9564 Median :-0.9418 Median :-0.6355
Mean :-0.9550 Mean :-0.9401 Mean :-0.6297
3rd Qu.:-0.9510 3rd Qu.:-0.9286 3rd Qu.:-0.5804
Max. :-0.9011 Max. :-0.8807 Max. : 0.0296
TimedomainBodyAccelerationJerkstdY TimedomainBodyAccelerationJerkstdZ TimedomainBodyAngularSpeedstdX
Min. :-0.9892 Min. :-0.9920 Min. :-0.9870
1st Qu.:-0.6766 1st Qu.:-0.8111 1st Qu.:-0.7603
Median :-0.6100 Median :-0.7816 Median :-0.7151
Mean :-0.5981 Mean :-0.7613 Mean :-0.7177
3rd Qu.:-0.5635 3rd Qu.:-0.7250 3rd Qu.:-0.6856
Max. :-0.0271 Max. :-0.4446 Max. :-0.3776
TimedomainBodyAngularSpeedstdY TimedomainBodyAngularSpeedstdZ TimedomainBodyAngularAccelerationstdX
Min. :-0.9851 Min. :-0.9879 Min. :-0.9919
1st Qu.:-0.7651 1st Qu.:-0.7178 1st Qu.:-0.7758
Median :-0.7134 Median :-0.6741 Median :-0.7323
Mean :-0.6842 Mean :-0.6468 Mean :-0.7269
3rd Qu.:-0.6304 3rd Qu.:-0.6032 3rd Qu.:-0.6896
Max. :-0.3990 Max. :-0.1331 Max. :-0.3890
TimedomainBodyAngularAccelerationstdY TimedomainBodyAngularAccelerationstdZ
Min. :-0.9933 Min. :-0.9934
1st Qu.:-0.8538 1st Qu.:-0.7956
Median :-0.8112 Median :-0.7508
Mean :-0.7880 Mean :-0.7386
3rd Qu.:-0.7137 3rd Qu.:-0.6806
Max. :-0.5460 Max. :-0.4822
TimedomainBodyAccelerationMagnitudestd TimedomainGravityAccelerationMagnitudestd
Min. :-0.9868 Min. :-0.9868
1st Qu.:-0.6549 1st Qu.:-0.6549
Median :-0.5972 Median :-0.5972
Mean :-0.5907 Mean :-0.5907
3rd Qu.:-0.5529 3rd Qu.:-0.5529
Max. :-0.1269 Max. :-0.1269
TimedomainBodyAccelerationJerkMagnitudestd TimedomainBodyAngularSpeedMagnitudestd
Min. :-0.99338 Min. :-0.9817
1st Qu.:-0.68473 1st Qu.:-0.7340
Median :-0.62566 Median :-0.6797
Mean :-0.62037 Mean :-0.6598
3rd Qu.:-0.57751 3rd Qu.:-0.5893
Max. :-0.03635 Max. :-0.2238
TimedomainBodyAngularAccelerationMagnitudestd FrequencydomainBodyAccelerationstdX
Min. :-0.9933 Min. :-0.9953
1st Qu.:-0.8386 1st Qu.:-0.6558
Median :-0.8037 Median :-0.6064
Mean :-0.7801 Mean :-0.5967
3rd Qu.:-0.7203 3rd Qu.:-0.5650
Max. :-0.5739 Max. : 0.1183
FrequencydomainBodyAccelerationstdY FrequencydomainBodyAccelerationstdZ
Min. :-0.9784 Min. :-0.9788
1st Qu.:-0.5907 1st Qu.:-0.7007
Median :-0.5426 Median :-0.6521
Mean :-0.5214 Mean :-0.6181
3rd Qu.:-0.4637 3rd Qu.:-0.5554
Max. : 0.1907 Max. :-0.1093
FrequencydomainBodyAccelerationJerkstdX FrequencydomainBodyAccelerationJerkstdY
Min. :-0.99446 Min. :-0.99041
1st Qu.:-0.71133 1st Qu.:-0.67741
Median :-0.64961 Median :-0.61291
Mean :-0.64648 Mean :-0.60335
3rd Qu.:-0.59903 3rd Qu.:-0.56099
Max. :-0.04166 Max. :-0.08012
FrequencydomainBodyAccelerationJerkstdZ FrequencydomainBodyAngularSpeedstdX
Min. :-0.9919 Min. :-0.9874
1st Qu.:-0.8306 1st Qu.:-0.7818
Median :-0.7968 Median :-0.7358
Mean :-0.7802 Mean :-0.7356
3rd Qu.:-0.7420 3rd Qu.:-0.7042
Max. :-0.5005 Max. :-0.4232
FrequencydomainBodyAngularSpeedstdY FrequencydomainBodyAngularSpeedstdZ
Min. :-0.9838 Min. :-0.9887
1st Qu.:-0.7671 1st Qu.:-0.7514
Median :-0.7152 Median :-0.7082
Mean :-0.6761 Mean :-0.6838
3rd Qu.:-0.6110 3rd Qu.:-0.6529
Max. :-0.3489 Max. :-0.2055
FrequencydomainBodyAccelerationMagnitudestd FrequencydomainBodyBodyAccelerationJerkMagnitudestd
Min. :-0.9863 Min. :-0.99263
1st Qu.:-0.7028 1st Qu.:-0.68354
Median :-0.6631 Median :-0.64109
Mean :-0.6614 Mean :-0.63483
3rd Qu.:-0.6241 3rd Qu.:-0.59059
Max. :-0.3235 Max. :-0.09778
FrequencydomainBodyBodyAngularSpeedMagnitudestd FrequencydomainBodyBodyAngularAccelerationMagnitudestd
Min. :-0.9814 Min. :-0.9935
1st Qu.:-0.7661 1st Qu.:-0.8499
Median :-0.7113 Median :-0.8100
Mean :-0.6969 Mean :-0.7949
3rd Qu.:-0.6541 3rd Qu.:-0.7385
Max. :-0.2724 Max. :-0.5937
activities subjects
Min. : NA Min. : 1.00
1st Qu.: NA 1st Qu.: 8.50
Median : NA Median :16.00
Mean :NaN Mean :15.71
3rd Qu.: NA 3rd Qu.:22.50
Max. : NA Max. :30.00
NA's :35
The following table relates the names used as prefix for the variables names present in the aggregated data set for mean() and std(). (XYZ) denotes three variables, one for each axis and is therefore not repeated to keep the table short.
Measurements for mean, all values are of class num
| Description | Time domain | Frequency domain |
|---|---|---|
| Body Acceleration (XYZ dimensions) | TimedomainBodyAccelerationmean(XYZ) | FrequencydomainBodyAccelerationmean(XYZ) |
| Gravity Acceleration (XYZ dimensions) | TimedomainGravityAccelerationmean(XYZ) | |
| Body Acceleration Jerk (XYZ dimensions) | TimedomainBodyAccelerationJerkmean(XYZ) | FrequencydomainBodyAccelerationJerkmean(XYZ) |
| Body Angular Speed (XYZ dimensions) | TimedomainBodyAngularSpeedmean(XYZ) | FrequencydomainBodyAngularSpeedmean(XYZ) |
| Body Angular Acceleration (XYZ dimensions) | TimedomainBodyAngularAccelerationmean(XYZ) | |
| Body Acceleration Magnitude | TimedomainBodyAccelerationMagnitudemean | FrequencydomainBodyAccelerationMagnitudemean |
| Gravity Acceleration Magnitude | TimedomainGravityAccelerationMagnitudemean | |
| Body Acceleration Jerk Magnitude | TimedomainBodyAccelerationJerkMagnitudemean | FrequencydomainBodyBodyAccelerationJerkMagnitudemean |
| Body Angular Speed Magnitude | TimedomainBodyAngularSpeedMagnitudemean | FrequencydomainBodyBodyAngularSpeedMagnitudemean |
| Body Angular Acceleration Magnitude | TimedomainBodyAngularAccelerationMagnitudemean | FrequencydomainBodyBodyAngularAccelerationMagnitudemean |
Measurements for standard deviation, all vlaues are of class num
| Description | Time domain | Frequency domain |
|---|---|---|
| Body Acceleration (XYZ dimensions) | TimedomainBodyAccelerationstd(XYZ) | FrequencydomainBodyAccelerationstd(XYZ) |
| Gravity Acceleration (XYZ dimensions) | TimedomainGravityAccelerationstd(XYZ) | |
| Body Acceleration Jerk (XYZ dimensions) | TimedomainBodyAccelerationJerkstd(XYZ) | FrequencydomainBodyAccelerationJerkstd(XYZ) |
| Body Angular Speed (XYZ dimensions | TimedomainBodyAngularSpeedstd(XYZ) | FrequencydomainBodyAngularSpeedstd(XYZ) |
| Body Angular Acceleration (XYZ dimensions) | TimedomainBodyAngularAccelerationstd(XYZ) | |
| Body Acceleration Magnitude | TimedomainBodyAccelerationMagnitudestd | FrequencydomainBodyAccelerationMagnitudestd |
| Gravity Acceleration Magnitude | TimedomainGravityAccelerationMagnitudestd | |
| Body Acceleration Jerk Magnitude | TimedomainBodyAccelerationJerkMagnitudestd | FrequencydomainBodyBodyAccelerationJerkMagnitudestd |
| Body Angular Speed Magnitude | TimedomainBodyAngularSpeedMagnitudestd | FrequencydomainBodyBodyAngularSpeedMagnitudestd |
| Body Angular Acceleration Magnitude | TimedomainBodyAngularAccelerationMagnitudestd | FrequencydomainBodyBodyAngularAccelerationMagnitudestd |
Activities and Subject fields
| Name | Description | class |
|---|---|---|
| activities | Activity measured | Factor w/ 6 levels |
| subjects | Subject id | int |
##Sources https://thoughtfulbloke.wordpress.com/tag/getting-and-cleaning http://vita.had.co.nz/papers/tidy-data.pdf