A chemical engineer is investigating whether a new catalyst increases the yield of a specific synthetic reaction. The yield, measured in grams per batch, is denoted by yyy. A random sample of 80 batches produced without the catalyst (Group 1) and an independent random sample of 120 batches produced with the catalyst (Group 2) were recorded. The results are summarized in the table below:
| Sample Group | Sample Size | ∑y\sum y∑y | ∑y2\sum y^2∑y2 | Unbiased estimate of mean | Unbiased estimate of variance |
|---|---|---|---|---|---|
| Without catalyst | 80 | 6240 | 492000 | yˉ1\bar{y}_1yˉ1 | s12s_1^2s12 |
| With catalyst | 120 | — | — | 81.5 | 380.4 |
Calculate the values of yˉ1\bar{y}_1yˉ1 and s12s_1^2s12.
Test, at the 1% level of significance, whether there is evidence that the mean yield is greater when the catalyst is used. State your hypotheses clearly.
Practise Edexcel A Level Maths Hypothesis Testing with the Normal Distribution with exam-style questions for A Level Maths. 132 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.