Historically, 45% of seedlings of a certain variety survive their first winter. A horticulturist believes that a new treatment increases this proportion and tests a random sample of 32 treated seedlings at the 5% significance level. The random variable X X\,X is the number that survive.
Find the least value of X X\,X for which the null hypothesis would be rejected.
Find the actual significance level of a test based on this critical region.
In the sample, 21 seedlings survive. State the conclusion of the test in context.
316 exam-style questions on OCR A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 The language of hypothesis testing, 2.5.2 Hypothesis test for a binomial proportion, 2.5.3 Inference and significance level, 2.5.4 Sample mean as a random variable (A-level only), 2.5.5 Hypothesis test for the mean of a normal distribution (A-level only), 2.5.6 Pearson's product-moment correlation coefficient, and 2.5.7 Hypothesis test using Pearson's coefficient (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.