The mean gross annual income of certified tack welders are normally distributed with the mean of $20,000 and a standard deviation of $2,000. The ship building association wishes to find out whether their tack welders earn more or less than $20,000 annually. The alternate hypothesis is that the mean is not $20,000. The 0.10 level of significance is to be used. What is the decision rule?
- Do not reject the null hypothesis if computed z lies between -1.96; otherwise, reject it
- None of these answers
- Reject the null hypothesis if computed z is below -1.96; otherwise, reject it
- Do not reject the null hypothesis if computed z lies greater than 1.645; otherwise, reject it
- Do no reject the null hypothesis if computed z lies between -1.645 and +1.645; otherwise, reject it
Answer(s): E
Explanation:
Since it is at the 10% significance level we must use z=+/-1.645. The null hypothesis Ho will not be rejected if the z-value falls between the critical value. We reject Ho if it falls beyond the critical level.
Reveal Solution Next Question