The weights of a random sample of 100 organic apples from an orchard had a mean of 185 g and a standard deviation of 12 g. The weights of a second random sample of 150 non-organic apples from the same orchard had a mean of 188 g and a standard deviation of 15 g.
Test, using a 5% level of significance, whether or not the mean weight of organic apples is less than the mean weight of non-organic apples. State your hypotheses clearly.
State two assumptions you made in carrying out the test in part (a).
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.