You measure the enzyme activity in 10 different extracts and find a sample mean of 2.2 mol min1 mg1 and a standard derivation of 0.15. Assuming that the 10 extracts represent an unbiased sample, = 2.2 is a point estimate of the true population mean, . a) If you sample another 10 extracts, how would you expect the two sample means to compare? Explain how you could use an interval to provide a better estimate of the population mean? [10 marks] b) Using a confidence interval of 90%, illustrate the relationship between above point estimate, confidence interval and z-score. What would happen to the confidence interval if you wanted to be 95% certain of it? Table 1 might be useful. [35 marks] c) In analytical method validation, explain how confidence intervals are used. [35 marks]. Commonly used z values for confidence intervals 90% =1.695, 95%= 1.96, 98%= 2.326, 99%= 2.576