Data Management Standard deviation question

Question

Hello, I am doing this question for my data managmnt class and would like to know how to go about it?

RJ has 20 minutes to get to his after school job. Despite his efforts,je os sfrequently late and has recorded his travel time (in minutes) as [18,20,22,27,16,23,25,26,19,28]. His boss has told him that unless he shows more consistency, he will lose his job. Over the next few weeks, RJ records his travel time as [22,20,22,24,24,25,21,19,21]. Should RJ lose his job? Include calculations to support your answer. (Also find the standerd deviation of both travel times)

Thank you very much for your time

Answer 1

Let's look at the first data set, when RJ was frequently late. To find the standard deviation, find the mean which is 22.4.

For each number, subtract the mean and square the result. Work out the mean of those squared differences, and you have the variance. Take the square root of the variance to find the standard deviation.

As you can see, using a computer or calculator is easier. On my TI-83 Plus, I find that the standard deviation = Sx = 4.0879.