RUGBY ACHIEVED ONLY
I wonder if rugby players in the forward position tend to be heavier than rugby players in the back position. I will investigate this using a random sample of 135 male rugby players from New Zealand and South Africa in the NZGrapher data base. I will use this data to answer my question.
I will use NZGrapher to make a comparative box and whisker plot with dots. I will also produce a summary of statistics for my sample.
Data:
Analysis
Central Tendency:
The average weight of forward players (110.5 kg) is more than the average weight of players in the backs (92 kg) in international test matches. This is indicated by the black line in the middle of the boxes.
Spread:
The IQR (middle 50%) for the forward pack is 12.5 kg whereas the IQR (middle 50% ) for backs is 8 kg. This indicates that there is more variation in the weights of forward players. Overall visually looking at the dot plot, the forward pack are more spread out than the backs.
Shape:
The shape of the graph (dot plot and the box and whisker is pretty symmetrical showing the bell curve. The shape of the graph for the forwards also has a bell curve but is skewed to the right since there is a tailing off of the dots to the right hand side.
Conclusion:
The graph shows that the average weights for forward players is greater than the average weight for backs in this data set. The dbm/ovs ratio is 0.64 and since this is greater than 1/3 I can make the call that the Forwards tend to be heavier on average than backs back in the population of International rugby players. This is confirmed by the median values in the summary statistics above. The median weight for the forwards is 110.5 kg and the median weight for the backs is 92kg.