Psychology 225 Final Exam Questions
and Verified Answers 100%
independent samples t-test - ✔✔compares the means of two different populations to see if
there is a significant difference between them
advantages - ✔✔Provide a simpler research design that requires each participant to complete
only one condition; eliminates risks of familiarity, fatigue, or carryover effects that can impact
the results.
disadvantages - ✔✔More susceptible to individual differences, as each group is different.
between subjects design - ✔✔two separate groups of people with each person in one group;
compare group results with independent samples t test
non directional (independent) null hypothesis - ✔✔no difference between the two group
means;
𝐻o: 𝜇1 = 𝜇2
non directional (independent) alternative hypothesis - ✔✔no difference between the two
group means;
𝐻a: 𝜇1 ≠ 𝜇2
independent null hypothesis - right tail - ✔✔there is no significant difference, or the mean of
group 1 is less than or equal to the mean of group 2; 𝐻o: 𝜇1 ≤ 𝜇2
independent alternative hypothesis - right tail - ✔✔the mean of group 1 is greater than the
mean of group 2; 𝐻a: 𝜇1 > 𝜇2
, independent null hypothesis - left tail - ✔✔there is no significant difference, or the mean of
group 1 is greater than or equal to the mean of group 2; 𝐻o: 𝜇1 ≥ 𝜇2
independent alternative hypothesis - left tail - ✔✔the mean of group 1 is less than the mean of
group 2; 𝐻a :𝜇1 < 𝜇2
degrees of freedom - independent - ✔✔df = 𝑛1 + 𝑛2− 2
t- test: independent - ✔✔x1 = group 1 mean
s1 = group 1 SD
n1 = group 1 sample size
x2 = group 2 mean
s2 = group 2 SD
n2 = group 2 sample size
p value assessment - ✔✔A p-value ≤ 0.05 (𝛼) indicates that statistically significant difference
between the means of the two groups being compared. Reject the null.
A p-value > 0.05 (𝛼) indicates there is insufficient evidence to conclude a meaningful difference
between the groups. We fail to reject the null hypothesis.
dependent samples t test - ✔✔the dependent samples t- test compares two different means;
the two means are related and this test compares the average difference in scores
advantages - ✔✔Controls for individual differences because the same participants are
measured twice or multiple times.
and Verified Answers 100%
independent samples t-test - ✔✔compares the means of two different populations to see if
there is a significant difference between them
advantages - ✔✔Provide a simpler research design that requires each participant to complete
only one condition; eliminates risks of familiarity, fatigue, or carryover effects that can impact
the results.
disadvantages - ✔✔More susceptible to individual differences, as each group is different.
between subjects design - ✔✔two separate groups of people with each person in one group;
compare group results with independent samples t test
non directional (independent) null hypothesis - ✔✔no difference between the two group
means;
𝐻o: 𝜇1 = 𝜇2
non directional (independent) alternative hypothesis - ✔✔no difference between the two
group means;
𝐻a: 𝜇1 ≠ 𝜇2
independent null hypothesis - right tail - ✔✔there is no significant difference, or the mean of
group 1 is less than or equal to the mean of group 2; 𝐻o: 𝜇1 ≤ 𝜇2
independent alternative hypothesis - right tail - ✔✔the mean of group 1 is greater than the
mean of group 2; 𝐻a: 𝜇1 > 𝜇2
, independent null hypothesis - left tail - ✔✔there is no significant difference, or the mean of
group 1 is greater than or equal to the mean of group 2; 𝐻o: 𝜇1 ≥ 𝜇2
independent alternative hypothesis - left tail - ✔✔the mean of group 1 is less than the mean of
group 2; 𝐻a :𝜇1 < 𝜇2
degrees of freedom - independent - ✔✔df = 𝑛1 + 𝑛2− 2
t- test: independent - ✔✔x1 = group 1 mean
s1 = group 1 SD
n1 = group 1 sample size
x2 = group 2 mean
s2 = group 2 SD
n2 = group 2 sample size
p value assessment - ✔✔A p-value ≤ 0.05 (𝛼) indicates that statistically significant difference
between the means of the two groups being compared. Reject the null.
A p-value > 0.05 (𝛼) indicates there is insufficient evidence to conclude a meaningful difference
between the groups. We fail to reject the null hypothesis.
dependent samples t test - ✔✔the dependent samples t- test compares two different means;
the two means are related and this test compares the average difference in scores
advantages - ✔✔Controls for individual differences because the same participants are
measured twice or multiple times.
