Cadbury states that the average weight of one of its chocolate products ‘Dairy Milk Silk’ is 60 g. As an analyst on the internal Quality Assurance team, you would like to test whether, at the 2% significance level, the average weight is 60 g or not. A sample of 100 chocolates is collected and the sample mean size is calculated to be 62.6 g. The sample standard deviation, as calculated from the sample, is 10.7 g.
Answer the following questions in order to draw a conclusion from the test.
The water purifier company Kent claims that the total hardness of the water after being treated and filtered by its product Kent RO is less than 300 ppm on an average. To test the claim, a water inspector takes a sample of 400 purifiers and calculates the mean total hardness of water being filtered out, which comes out to be 296 ppm, with a standard deviation of 25 ppm. The hypothesis test is to be conducted at a significance level of 3%.
Now answer the following questions.