It takes an average of 12.4 minutes for the blood to begin clotting after an injury. An EMT wants to see if the average will increase if the patient is immediately told the truth about the injury. The EMT randomly selected 57 injured patients to immediately tell the truth about the injury and noticed that they averaged 12.8 minutes for their blood to begin clotting after their injury. Their standard deviation was 3.84 minutes. What can be concluded at the αα = 0.01 level of significance?

1. For this study, we should use the Select an answer t-test for a population mean z-test for a population proportion
2. The null and alternative hypotheses would be:

H0:H0:? μ p Select an answer < = > ≠

H1:H1:? μ p Select an answer = > < ≠

3. The test statistic? z t = (please show your answer to 3 decimal places.)
4. The p-value = (Please show your answer to 4 decimal places.)
5. The p-value is ? > ≤ αα
6. Based on this, we should Select an answer fail to reject accept reject the null hypothesis.
7. Thus, the final conclusion is that ...
   • The data suggest the population mean is not significantly greater than 12.4 at αα = 0.01, so there is statistically significant evidence to conclude that the population mean time for blood to begin clotting after an injury if the patient is told the truth immediately is equal to 12.4.
   • The data suggest that the population mean is not significantly greater than 12.4 at αα = 0.01, so there is statistically insignificant evidence to conclude that the population mean time for blood to begin clotting after an injury if the patient is told the truth immediately is greater than 12.4.
   • The data suggest the populaton mean is significantly greater than 12.4 at αα = 0.01, so there is statistically significant evidence to conclude that the population mean time for blood to begin clotting after an injury if the patient is told the truth immediately is greater than 12.4.