A national car dealer has been running job enrichment workshops for its sales consultants over the past three years. To establish if these programmes have been effective, the human resource manager conducted a study amongst the sales consultants to measure their degree of job satisfaction on a 10-point rating scale (1 = low job satisfaction; 10 = high job satisfaction).

A random sample of 22 sales consultants who had not attended a job enrichment workshop had a mean rating score on job satisfaction of 6.9. The mean rating score on job satisfaction for 25 randomly selected sales consultants who had attended a job enrichment workshop was 7.5.

Assume that the population of rating scores for each group of sales consultants is normally distributed. Also assume a population standard deviation of rating scores for non-attendees of 1.1, and for attendees of job enrichment workshops assume a population standard deviation of rating scores of 0.8.

Can the human resource manager conclude, at the 5% significance level, that the job enrichment workshops increase sales consultants' job satisfaction levels? Present your findings to the human resource manager.