Chapter 8, Problem 50SE

Flaws The null hypothesis on true/false tests is that the student is guessing, and the proportion of right answers is $\mathrm{0.50.}$ A student taking a five-question true/false quiz gets 4 right out of 5. She says that this shows that she knows the material, because the one-tailed p-value from the one-proportion $z\text{-test}$ is $0.090,$ and she is using a significance level of $\mathrm{0.10.}$ What is wrong with her approach?