Construct a 95% confidence interval for the difference in the true mean delivery times for Courier 1 and 2
A law firm is evaluating the delivery of two courier delivery services in Cape Town. They believe that there is a difference between the average delivery times for the two career services. To investigate this matter further, the firm decides to use both courier services daily over a two month for deliveries to similar destinations. The delivery times for each Courier servers are recorded over the two month period. It is found that Courier 1 was used by the firm 12 times and the average delivery time was 43 minutes with a standard deviation of 12 minutes. Courier to was used 15 times, and the average delivery time was 36 minutes with a standard deviation of 8 minutes. Construct a 95% confidence interval for the difference in the true mean delivery times for Courier 1 and 2 (rounded off to two decimals).
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