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Conditions for a z test about a proportion


Moussa saw a commercial on television that claimed 9 out of 10 dentists recommend using a specific brand of chewing gum. He suspected that the true proportion was actually lower, so he took an
of 50 dentists and asked whether or not they recommend using that brand of chewing gum. He wants to use the sample data to test H0:p=0.9 versus Ha:p<0.9, where p is the proportion of all dentists that recommend this brand of chewing gum.
Which conditions for performing this type of test did Moussa's sample meet?
Choose all answers that apply: