Suppose a random survey is conducted of 9 U.S mothers who recently weaned their children. The average weaning age was 21.1 months with a standard deviation of 5.8 months. Conduct a hypothesis test to determine if the average weaning age in the U.S, is less than 12 months old. Use a 5% level of confidence.

Show you hypothesis, calculated z or t score, and decision to accept or not accept the null hypothesis