# Thread: Distribution problems

1. ## Distribution problems

The question is:

The general manager of a logistic consulting group believes that 28% of the firm's orders come from new customers. A simple random sample of 120 orders was taken. Assuming the manager's claim is valid determine (to 3 dec. places)

1. The standard error for the sampling distribution proportion (i got 0.041.. is that wrong?)

2. The probability that there is a difference of at least 3% between the percentage of new customers found by taking the sample and that claimed by the manager. (really don't not too sure how to do this one)

2. I'm a little puzzled by the question. The percentage is speculative, so why should it be used in the caluclation of the variance or standard error? What were the results of the survey? That proportion may be more valid. In the absence of additional data, I'm inclined to use 0.5, giving 0.0456, quite a bit larger than your value.

1) Let's decide this, first.
2) Make sure this is the ENTIRE problem statement.