Question

A producer claims that the proportion of its customers who cannot distinguish regular product
from their light product is at most 0.12. The producer decides to test this null hypothesis
against the alternative that the true proportion is more than 0.12. The decision rule adopted is
to reject the null hypothesis if the sample proportion who cannot distinguish between these two
products exceeds 0.15. If a random sample of 100 customers is chosen, what is the probability
of a Type I error, using this decision rule? (z0.92=0.8212)

Answer 1

P(Type I error) = P(reject H0 when Ho is true) = P(phat>0.15 when p₀=0.12)

Ans : 0.1788