Standard +0.3 This is a standard one-tailed hypothesis test for a proportion using normal approximation. It requires routine application of the binomial test procedure: stating hypotheses, calculating test statistic, finding critical value, and reaching a conclusion. The calculations are straightforward with no conceptual challenges beyond A-level statistics curriculum, making it slightly easier than average.
It is known that 20% of plants of a certain type suffer from a fungal disease, when grown under normal conditions. Some plants of this type are grown using a new method. A random sample of 250 of these plants is chosen, and it is found that 36 suffer from the disease. Test, at the 2% significance level, whether there is evidence that the new method reduces the proportion of plants which suffer from the disease. [7]
It is known that 20% of plants of a certain type suffer from a fungal disease, when grown under normal conditions. Some plants of this type are grown using a new method. A random sample of 250 of these plants is chosen, and it is found that 36 suffer from the disease. Test, at the 2% significance level, whether there is evidence that the new method reduces the proportion of plants which suffer from the disease. [7]
\hfill \mbox{\textit{OCR PURE Q12 [7]}}