The chance that a webpage visitor clicks a link is 0.15. Angela believes that increasing the link's font size increases the click probability. After the change, 20 of a random sample of 90 visitors click.
Use H0:p=0.15H_0:p=0.15H0:p=0.15, H1:p>0.15 H_1:p>0.15\,H1:p>0.15 and, under H0H_0H0, X∼B(90,0.15)X\sim B(90,0.15)X∼B(90,0.15).
Explain why an upper-tailed test is appropriate.
Calculate the exact p-value.
State the decision at the 5% level and give a conclusion in context.