Exam 3: The Phoenix of Statistics

You have just joined the sales modelling team for a start-up software company. Your boss has decided that from now on the team will adopt a Bayesian approach. However, not all staff understand what this is; your boss asks you to present a training session. How would you explain a Bayesian approach in your session introduction?

A researcher in a Human Resources Unit presented a recent study, which showed a statistical significance between length of staff lunch breaks and low productivity; how can she explain to her manager that this does not mean that the length of staff lunch breaks should be reduced?

Your business studies lecturer has devoted the past ten weeks to teaching you the Bayesian approach and is now asking that you offer a critique of it. What key criticism could you raise?

An HR manager was interested in employee use of company on-site gyms across twenty sites. Different researchers collected and analysed data across each of the sites but the resultant twenty reports showed differing p-values, some sites found a statistical significance between opening hours of on-site gyms and employee usage and others did not. Which of the following would it useful for her to review?

A trainee data analyst for a large social media company, which has falling site usage, has just completed a study into factors that affect site users' satisfaction levels. However, he finds only one statistically significant factor, which he includes in his report but he deliberately, omits the other six non-significant findings. What is the term for what the data analyst has done?

Which of the following is not a factor in data analysts' over-use of p-values and NHST in business and marketing research?

Your CEO has followed your advice and now wants you to measure effect sizes. You report a Pearson's r of 0.50 for the impact of Unblock Me Now drain cleaner on reducing drain blockage time. Your CEO wants to know if this is bad, as she remembers that a p-value of 0.30 is not good. What do you tell her?

A recruitment analyst wanted to examine the likelihood that advertising on social media is more effective than in print media for recruiting the best candidates. She conducted one study where the probability of making a Type I error was 0.05 and a Type II error was 0.2. Does her research have empirical probability?

A human resources manager in the IT sector was concerned about unconscious bias in recruitment panels. There were two posts and seven candidates, four men and three women. Theoretically, all the candidates have an equal probability of being hired as they all match the selection criteria. However, the manager has data that suggests that it is more likely men will be hired based on data from across the IT sector and within her own company. However, the manager has implemented many equality initiatives within her company and therefore wants to determine the probability that still no women will be hired. What formula could she use to determine this probability and assess the impact of unconscious bias in her company's recruitment?

You are the CEO of a small financial forecasting company. You have decided to adopt a Bayesian approach to data analysis and modelling. When you announce this new policy, your staff are unhappy and unconvinced, as they are used to a NHST approach. You stress that the Bayesian approach has several key advantages, including which of the following.

A researcher was assessing customer satisfaction with MakeMebeautiful, a new beauty product. He had a sample size of 75 and a p-value of 0.10. Does the researcher recommend that the company stop promoting this product?

A researcher working in a Human Resources department was interested in gender and sales figures so he conducted a t-test. The mean for males was 66.25 and the mean for females was 78.24, with both groups having a standard deviation of 7. What is the effect size using Cohen's d?

In our previous example, the human resources manager had already calculated the probability of no women being hired based on sector wide data. In the Bayesian approach, what sort of probability is this?

You lead a product-testing unit for a large pharmaceutical company. Your team has conducted forty trials of a new antibiotic but you are not sure if the results are conclusive enough to urge the company to start producing the new drug. A new data analyst has joined your team suggesting that meta-analysis might be a good idea, do you agree?

Your CEO has just read a book on criticisms of the NHST and worries that all company data analysis is now flawed and will lead to huge financial losses. How might you reassure her?

A stockmarket trader conducted a Bayesian analysis of variations in skirt length and stock market growth. He calculated a Bayes factor of 1. Should he use skirt length as a predictor of stock market growth?