A researcher in a Veterans Affairs hospital wants to determine whether patients who had metal-on-metal hardware versus ceramic-on-metal hardware used for their hip replacements have different levels of chromium ions in their blood 2 years later. She measures chromium ions in mcg/mL or parts per billion (ppb) from 0 and up. She collects a sample of all the patients who had total hip replacements with these two types of hardware at the hospital in the last 2 years. She enrolls a total of 145 subjects in the study and the researcher sets her alpha at 0.05 and her power at 0.8. The average serum chromium in the metal-on-metal groups is 0.78 ppb, and the average serum chromium in the ceramic-on-metal hardware is 0.45. The t-test results have a p-value of 0.043. What conclusion should the researcher draw about the null hypothesis? and why