An long distance swimmer has established a mean time to swim a half-marathon (5 kilometres) of 131 minutes with a population standard deviation of 34.2 minutes. Their coach coach believes they could swim faster with a new cold-water bodysuit. To test the suit over the span of a few months, the swimmer was timed for 12 half-marathon swims which resulted in a sample mean of 121.6 minutes. The z-test is to be conducted at the 10% level of significance. What is the value of the calculated test statistic? State just the numerical value of your answer without symbols or units (use a negative sign if required). Though we discuss z or t statistics usually within -3 and +3, you may get much larger or much smaller values. This does not mean you have made an error.