Week 2 Python Data Analysis Interpretation:
Frequency Distribution of First Variable: NUMBER_LAYERS
The Mars crater database contains a record of the number of layers each impact crater ejecta has. This record is represented by the NUMBER_LAYERS variable. Of the total 384,343 craters studied, about 94.87% do not have ejecta layers. However, 15,467 craters have 1 ejecta layer, making up 4.02% of the total crater population.
0.89% and 0.19% of craters have 2 to 3 number of ejecta layers respectively. The highest number of ejecta layer is 5; with only 5 Mars craters (0.001 %) making it into this ejecta layer category.
The next step in the analysis will be to check if there is a relationship between number of ejecta layers and crater depth or diameter.
Frequency Distribution of Second Variable: MORPHOLOGY_EJECTA_3
The craters were divided into 3 morphology groups based on crater ejecta shape: MORPHOLOGY_EJECTA_1, MORPHOLOGY_EJECTA_2 and MORPHOLOGY_EJECTA_3. Each group was further subdivided into different morphology classes based on different naming conventions. The second variable to be examined is MORPHOLOGY_EJECTA_3 group, which contains 28 individual morphology classifications.
The frequency table above shows that 349 craters belong to the Pin-Cushion morphology class, which is equivalent to 0.09% of the total crater population. This is followed by the Small-Crown and Pseudo-Butterfly morphology categories with 264 (0.07%) and 118 (0.03%) craters respectively. The rest of the morphology categories were only observed in small number of craters.
However, majority of the craters, 383,050 craters making up 99.66% of the total crater population, were not classified and therefore were reported as missing values.
The next step of this analysis will be to find out if the available morphology data is sufficient to answer the already framed research questions.
Frequency Distribution of Third Variable: MORPHOLOGY_EJECTA_2
The third variable to be examined is MORPHOLOGY_EJECTA_2 group, which contains 103 individual morphology classifications.
The frequency table above shows that there are 103 different morphology categories within the MORPHOLOGY_EJECTA_2 group. However, only a few morphology categories were observed in more than 10 different craters out of the 384,343 Mars craters in the study database.
364, 867 craters (94.93%) out of the total 384, 343 craters were not classified into any morphology category and therefore were reported as missing values. The HuSL and HuBL morphology categories occurred 6,109 and 4,424 times (1.59% and 1.15%) respectively. This is followed by SmSL, HuAm, Hu, SmBL, SmAm, Sm and HuSL/SmSL morphology categories, which were identified in different number of craters, ranging between 2,713 and 204. The rest of the morphology categories have less than 80 crater occurrences each.
First part of week 2 assignment.
1. Python Data Analysis Code (Week 2): click here to view
Posted on December 06, 2015 by Okechukwu Ossai