Assume that each of the following conclusions represents an error in hypothesis testing. Indicate whether each of the statements is a Type I or II error.

a. Based on the data, the null hypothesis is rejected.

b. There is no significant difference in quality of care between nurses who work 8- and 12-hour shifts.

c. There is a significant difference between right- and left-handers in their ability to perform a spatial task.

d. The researcher fails to reject the null hypothesis based on these data.