A researcher examined the effect of background noise level on memory performance of college students. Students were randomly assignment to one of two groups. Students in the first group were given a memory test in a room with a low level of background noise and students in the second group were given the memory test in a room with a high level of background noise. The memory scores of the two groups are shown below. Set alpha at 05 and determine if background noise level had a significant effect on memory scores. Low noise level scores: 8, 10, 6, 8, 10,6 (SD = 1788854) High noise level scores: 1,3,4,7,5, 4 (SD = 2) What type of test is this? Select one: O a z-test O b. Independent-samples t-test O c. One-sample t-test O d. Dependent-samples t-test