According to an IRS study, it takes a mean of 330 minutes for taxpayers to prepare, copy, and electronically file a 1040 tax form. This distribution of times follows the normal distribution and the standard deviation is 80 minutes. A consumer watchdog agency selects a random sample of 40 taxpayers.

What is the likelihood the sample mean is greater than 320 minutes? 4 decimals

What is the likelihood the sample mean is between 320 and 350 minutes? 4 decimals

What is the likelihood the sample mean is greater than 350 minutes? 4 decimals

What is the probability that the sampling error would be more than 20 minutes? 2 decimals