The probability that a visitor to a webpage clicks on a particular link is 0.15. Angela increases the font size of the link and believes that this will increase the probability of a visitor clicking on it. After the change, 20 of a random sample of 90 visitors click on the link.
State the null and alternative hypotheses, using p p\,p for the population probability that a visitor clicks on the link after the change.
Calculate the probability, assuming the null hypothesis is true, of obtaining at least 20 clicks.
Complete the hypothesis test at the 5% level of significance.