In 1997, 4% of mothers smoked more than 21 cigarettes during their pregnancy. An obstetrician believes that the percentage of mothers who smoke 21 cigarettes or more is less than 4% today. She randomly selects 120 pregnant mothers and ﬁnds that 3 of them smoked 21 or more cigarettes during pregnancy. Does the sample data support the obstetrician’s belief? Use the α = 0.05 level of signiﬁcance.
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