Question 975838: The college cafeteria finds that 30 percent of students will buy a dessert if it is properly advertised. The cafeteria manager is thinking of hiring an arts student to create a poster of a new apple and ice cream dessert which can be displayed at the front entrance to the cafeteria during the lunch hours. Normally, 650 students use the cafeteria during lunch time. What is the probability that more than 35 percent of the students will buy the apple and ice cream dessert?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! One sample proportion test looking for
z=(.35-.30)/sqrt[(0.30)(0.70)/650];;;; denominator is .
z=0.05/0.0179
=2.793
What is this? It is the probability that more than 35% will buy the desert given that 30% is the base probability.
It is 0.0026.
With a large sample size, the likelihood of this occurring by chance will be small. Note, the calculator gives a different result, because you are using 228 students for 35%, not the exact 227.5.
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