Need help on the practice problem below on section b.

Specifications for a part for a DVD player state that the part should weigh between 24.9 and 25.9 ounces. The process that produces the parts has a mean of 25.4 ounces and a standard deviation of .22 ounce. The distribution of output is normal. Use Table-A.

a.What percentage of parts will not meet the weight specs? (Round your "z" value and final answer to 2 decimal places. Omit the "%" sign in your response.)

Percentage of parts2.32% (This one i got right)

b.Within what values will 99.74 percent of sample means of this process fall, if samples of n = 12 are taken and the process is in control (random)? (Round your answers to 2 decimal places.)

Lower value ? Upper value ?