Weight gained in twin pregnancies. A group of researchers established age-standardized charts reporting weight gain during term twin pregnancies in Southeast China in the BMC Pregnancy Childbirth (Vol. 20, 2020). They conducted a retrospective study on a data set of 884 women pregnant with twins who had a gestational age beyond 36weeks. They claimed that the average weightgained by the women was more than or equal to 2500g. Set up the null and alternative hypotheses to test this claim.