Anumber changed to 12.6 after it was rounded. to what place was the number rounded

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Type the correct answer in each box. use numerals instead of words. if necessary, use / for the fraction bar. consider the given table.

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?