I am having a difficult time with this practice problem. Any help would be greatly appreciated. TIA!

A manufacturer must test that his bolts are 1.00 cm long when they come off the assembly line. He must recalibrate his machines if the bolts are too long or too short. After sampling 121 randomly selected bolts off the assembly line, he calculates the sample mean to be 0.94 cm. He knows that the population standard deviation is 0.31 cm. Assuming a level of significance of 0.05, is there sufficient evidence to show that the manufacturer needs to recalibrate the machines? Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Ho : H = 1.00 Ha : H 1.00 Answer 2 Points Tables Keypad Keyboard Shortcuts 0 > O