Suppose a baker claims that her bread height is less than 15 cm, on average. several of her customers do not believe her, so the baker decides to do a hypothesis test at a 5% significance level, to persuade them. she bakes loaves of bread. the mean height if the sample loaves is 13 cm. the baker knows from experience that the standard deviation for her bread height is 1.2cm.

what is the test statistic of this one-mean hypothesis test, rounded to two decimal places?