A construction company wants to determine if the likelihood of having an injury is related to the type of worker. Over the past decade the company has had an average total workforce of 2560 workers. On average 601 of these were tradesmen, 381 were apprentices and the rest were labourers. During that decade there was a total of 424 workers injured, 102 of these were tradesmen, 46 of these were apprentices, and the rest were labourers.
1) Calculate the number from this data that can be used to test for independence.
2)what is the critical value at the 1% significance level if the null hypothesis is that whether someone has an accident is independent of the type of worker?
3)We should reject the null hypothesis and conclude that the type of worker and whether or not they had an accident are not independent if the value calculated in Question (1) is:
a) less than the value in Question (2).
b) greater than the value in Question (2).
This solution explains how to construct and evaluate hypothesis tests for a construction company considering the impacts of job roles on injuries. There is also a part explaining how to test for independence.