Question

Professor Smith would like to see if giving the students chocolate made a difference in their levels of happiness. The students were asked to rate how happy they felt on a 1(not happy at all) to 10(the happiest they have ever been) level before they were given chocolate and after. Please use the following data for questions a-d.

1. 1. Calculate the t value
2. 2. What are the critical values at the .05 and .01 significance levels?
3. 3. What is the interpretation of the obtained value at .05 and .01 levels of significance?
   4. Write up the results at p = .05 in APA format.

Pretest	Post-Test
2	5
4	5
3	6
4	5
5	7
6	8

Answer 1

(a)

Values of d = Pretest - Post test are got as follows:

- 3, - 1, - 3, - 1, - 2, - 2

From the d values the following statistics are calculated:

n = 6

= - 12/6 = - 2

s_d = 0.8944

SE = s_d/

= 0.8944/ = 0.3651

Test statistic is:

t = - 2/0.3651 = - 5.48

So

test static is:

- 5.48

(b)

(i)

For = 0.05

ndf = n - 1 = 6 - 1 = 5

From Table, critical values of t = 2.5706

(ii)

For = 0.01

ndf = n - 1 = 6 - 1 = 5

From Table, critical values of t = 4.0321

(c)

(i)

For = 0.05:

Since calculated value of t = - 5.48 is less than critical value of t = - 2.5707, the difference is significant. Reject null hypothesis.

Conclusion:
The data support the claim that giving the students chocolate made a difference in their level of happiness.

(ii)

For = 0.01:

Since calculated value of t = - 5.48 is less than critical value of t = - 4.0321 the difference is significant. Reject null hypothesis.

Conclusion:
The data support the claim that giving the students chocolate made a difference in their level of happiness.

(d)

The results are:

The data support the claim that giving the students chocolate made a difference in their level of happiness.