The critical value of z for this test will therefore be 1.65.Ĩ. For a 1-tailed test, you need a z greater than 1.65.

If you are using the 95% confidence level, for a 2-tailed test you need a z below -1.96 or above 1.96 before you say the difference is significant. Determine the critical value for a 95% level of confidence (p<0.05). Would you be doing a 1-tailed test or a 2-tailed test?īecause the hypotheses contain reference to the direction of the difference, this one involves a 1-tailed test.ħ. Then determine the critical region for a level of significance of p< 0.05.Ħ. Formulate the research and null hypotheses needed to test this contention. Draw a normal curve, mark it with z values and ages, and shade the critical region.īecause it is a 2-tailed test, either a positive or a negative difference will be relevant.ĥ.The advertising department of Wired Xers argued that, in fact, its readers were younger than those of Quiche & Volvo. The critical value for a 95% two-tailed test is ± 1.96.Ĥ. Since the hypotheses are about the existence of a difference between the two means and not the direction of the difference, it would be a two-tailed test.ģ. Would you be doing a 1-tailed test or a 2-tailed test? Formulate a pair of research and null hypotheses to test this claim.Ģ. The advertising department of Quiche & Volvo claims that the age of its average subscriber is not the same as the average subscriber of Wired Xers. Their marketing department identified two magazines, Wired Xers and Quiche & Volvo as being especially popular among their target population. wants to focus its marketing for a new compact disc player on young affluent professionals.

Z score for 98 confidence interval