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...

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.

1. 
   

   What is the standard error of the mean in this example?(Round your answer to 3 decimal places.)
   

   
   


2. 
   

   What is the likelihood the sample mean is greater than 320 minutes?(Roundz value to 2 decimal places and final answer to 4 decimal places.)
   

   
   

A normal population has a mean of 75 and a standard deviation of 5. You select a sample of 40.

Compute the probability that the sample mean is:

1. 
   

   Between 74 and 76.

   
   


2. 
   

   Between 76 and 77.

   
   


3. 
   

   Greater than 77.