Quant t critical

Question about Quant: When does t critical become negative number? In page 276 Quant part in CFAI book, it shows -2.345 when I think it should be only 2.345 without the negative sign (same as schweser page 178) Really appreciate the explanation.

I was referring to one-tailed test

Yes, it is confusing… One tailed test, when the parameter is -ve, could be on other side … Better… create a confidence interval = b0± std error*tc and see that intercept term is not greater than -10% ( i.e. it falls in the confidence interval at 1% significance …confi interval = -7.6% to - 15.6%)…