Table of Contents
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Slide 3- Research Design
Slide 4-Threats to Internal Validity
Slide 5- Threats to External Validity
Slide 6-Data
Slide 7- Weight Before And After Intervention Graph
Slide 8-Data
Slide 9-Test Grades on the Food Pyramid Before and After
Intervention Graph
• Slide 10-Correaltion graph-Intervention vs. Playing in Gym
• Slide 11-Correaltion graph-Junk Food vs. Report Card
Grades
• Slide 12- References
Research Design
• The pre-experimental design I am going to
implement for my research is One-Group
Pretest-Posttest Design. The symbolic design
for this research is OXO, this mean that a
single group will be pretested (O), exposed to
a treatment (X), and then post-tested (O).
Threats to Internal Validity
• History- This can be a threat because once the child leaves the classroom there is
no control what happens at home or at the park or elsewhere.
• Maturation- This is a threat to my study because I am working with the middle
school population and they are growing rapidly. Over a four week span I can see
some of them gaining weight not necessarily because of what they are eating or
not eating but because of the changes and growth going on in their body.
• Testing/ Pre-test Sensitization- I can see this being a threat with my students
because if they see a similar test/survey for the second time they may not take it
seriously.
• Statistical Regression- this might be a threat considering the participants are all
different and are at different physical levels.
• Differential Selection of Subject- This is a threat because my subjects are growing
at a rapid pace and they will be physically different as well as mentally different
from the start to the end.
• Selection- Maturation Interaction- Yes this poses as a threat because my results
may be skewed due to the different growing rates especially amongst the boys.
Threats to External Validity
• Generalizable Conditions- I think that this can be a threat because the same
project can be duplicated and there may be different results.
• Selection- Treatment Interaction- This is a major threat because my
subjects are not random. They are all in special Ed, in the same school same
class and same grade. If the selection was more random I think the results
would be more reliable.
• Specificity of Variables- I will try my hardest not to make this a threat and
will try to make my variables operate as efficiently as possible.
• Experimenter Effects- I think this will be a threat because the participants
may have prior knowledge about the food pyramid or what obesity is.
• Reactive Arrangements/ Participants Effects- I think this can be a threat
because the children can lie on the post survey because of the placebo
effect of because they feel the need to impress me and showed that they
learned something.
Pre-Intervention/Post Intervention
Data
Weight Pre Intervention
Weight Post Intervention
Student A
83
81
Student B
100
96
Student C
81
84
Student D
115
115
Student E
145
135
Student F
98
92
Student G
135
128
108.1428571
104.4285714
Mean
Weight Before And After Intervention
160
140
120
100
Weight
80
Weight Pre Intervention
60
Weight Post Intervention
40
20
0
Students
Pre-Intervention/Post Intervention
Data
Test Grade Pre Intervention
Test Grade Post Intervention
Student A
55
85
Student B
61
72
Student C
78
81
Student D
33
65
Student E
52
97
Student F
87
88
Student G
49
46
59.28571429
76.28571429
Mean
Test Grades on the Food Pyramid
Before and After Intervention
120
100
80
Test
Scores 60
Test Grade Pre
Intervention
40
Test Grade Post
Intervention
20
0
Students
Intervention vs. Playing in Gym
Number of Children Receiving
Intervention
10
9
8
7
6
5
4
3
2
1
0
0
Y=# of children receiving intervention
X=# of children playing in gym
2
4
6
8
Number of Children Playing in Gym
10
Number of Children who Eat Junk
Food
Junk Food vs. Report Card Grades
10
9
8
7
6
5
4
3
2
1
0
0
Y=# of Children Who Eat Junk Food
X= Low Report Card Grades
2
4
6
Low Report Card Grades
8
10
References
• O’Connor-Petruso, S. (2013). Descriptive
Statistics Threats to Validity [PowerPoint
slides].Retrieved
from https://bbhosted.cuny.edu/webapps/por
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