Activity 2.1.3: Making Results
Meaningful
Introduction
In the last activity, you saw how easy it is to manipulate and misinterpret data. When
conducting scientific research, data analysis is essential to drawing meaningful
conclusions from experimental results. In order to prevent data manipulation and
misinterpretation, scientists use statistics (the collection, organization, and
interpretation of numerical data) to objectively analyze experimental data. In this
activity you will learn one process that scientists use to statistically analyze data.
You will use this process to analyze the results of a scientific investigation.
Equipment






Computer with Internet access and presentation software
Statistical Analysis presentation
Statistical Analysis Resource Sheet
Activity 2.1.3 Student Response Sheet
Scientific calculator
Laboratory journal
Procedure
1. Take notes in your laboratory journal as your teacher presents the Statistical
Analysis presentation.
2. Answer Conclusion questions 1 – 5. Refer back to your notes or to the Statistical
Analysis presentation as needed.
3. Obtain pages 1 – 4 of the Statistical Analysis Resource Sheet from your teacher.
4. Obtain a Student Response Sheet from your teacher or from the mission file.
5. Follow all of the steps to statistically analyze the practice problem found on Part
I: Example One of the Student Response Sheet. Make sure to show all work.
You may use the Statistical Analysis Resource Sheet as well as the notes you
took in your laboratory journal to help you. For all of your calculations, round your
decimals to the nearest hundredths.
6. When you have completed all of the steps, show your work to your teacher and
obtain the remainder of the Statistical Analysis Resource Sheet.
7. Compare your answers on Part I of your Student Response Sheet to the answers
outlined in Example One on the Statistical Analysis Resource Sheet.
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8. Answer Conclusion question 6.
9. Read through the remainder of the examples on the Statistical Analysis
Resource Sheet.
10. Note that your teacher will assign you and a partner one of the four studies found
below.
11. Work with your partner to statistically analyze the results of your assigned study.
Record your answers on Part II: Assigned Study of the Student Response Sheet.
Make sure to show all of your calculations.
12. Have your teacher initial and date that you have successfully completed the
statistical analysis on your Mission Completion Task list.
13. Make notes on the corresponding Notes section on your Mission Completion
Task list.
14. Answer Conclusion question 7.
Study One
It is known that on average, adult males tend to have lower resting heart rates than
females. A sports physiologist specializing in teenagers was interested in determining
whether the same holds true for teenagers age 14 through 17. It was hypothesized that
teenage males have lower resting heart rates than teenage females. To investigate this
hypothesis, a researcher randomly selected 29 males and 29 females from PBS classes
across the United States to determine whether the males enrolled in the class have
lower resting heart rates than the females enrolled in the class. The participants’ heart
rates were measured for two minutes while seated and resting and the average heart
rate was calculated. The results of the experiment are listed in the following chart.
Females Resting Heart Rate (bpm)
67
95
93
85
100
99
104
101
108
93
94
102
84
85
100
93
90
105
Males Resting Heart Rate (bpm)
90
74
83
94
72
87
86
84
70
69
92
84
84
97
100
96
90
74
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99
91
101
104
107
107
98
107
109
83
100
83
94
72
90
74
83
94
72
87
86
84
Study Two
A sports physiologist was interested in determining how short amounts of moderate
exercise affect the heart rate of female teenagers. It was hypothesized that the average
heart rate of teenage females after jogging for three minutes would be significantly
higher than their resting heart rates. To investigate this hypothesis, a researcher
randomly selected 21 females age 14 through 17 from PBS classes across the United
States. The researcher compared their resting heart rates to their heart rates after
jogging for three minutes. The participants’ resting heart rates were measured for two
minutes while seated and resting and the average resting heart rate was calculated.
The participants then jogged in placed for three minutes. Immediately after jogging, the
participants’ heart rates were measured again for two minutes and the average heart
rate after jogging was calculated. The results of the experiment are listed in the
following chart.
Average Resting Heart Rate (bpm)
100
75
96
98
103
84
93
116
87
97
93
86
76
97
72
72
72
70
Average Heart Rate After Jogging for 3
Minutes (bpm)
120
97
169
147
141
120
167
158
129
145
135
96
147
133
123
123
125
74
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76
67
95
107
120
125
Study Three
A sports physiologist was interested in determining how short amounts of moderate
exercise affect the heart rate of male teenagers. It was hypothesized that the average
heart rate of teenage males after jogging for three minutes would be significantly higher
than their resting heart rates. To investigate this hypothesis, a researcher randomly
selected 21 males age 14 through 17 from PBS classes across the United States. The
researcher compared their resting heart rates to their heart rates after jogging for three
minutes. The participants’ resting heart rates were measured for two minutes while
seated and resting and the average resting heart rate was calculated. The participants
then jogged in placed for three minutes. Immediately after jogging, the participants’
heart rates were measured again for two minutes and the average heart rate after
jogging was calculated. The results of the experiment are listed in the following chart.
Average Resting Heart Rate (bpm)
90
74
83
94
72
87
86
84
70
69
92
84
84
97
100
96
90
74
83
94
72
Average Heart Rate After Jogging for 3
Minutes (bpm)
136
120
142
149
125
99
138
184
160
78
103
128
110
148
118
121
136
120
142
149
125
Study Four
A sports physiologist was interested in determining whether there is a difference in how
short amounts of moderate exercise affect the heart rate of male teenagers versus
female teenagers. It was hypothesized that the change in average heart rate of teenage
males before and after jogging for three minutes would be lower than the change in
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average heart rate of teenage females before and after jogging for three minutes. To
investigate this hypothesis, a researcher randomly selected 21 males and 21 females
age 14 through 17 from PBS classes across the United States. The participants’ resting
heart rates were measured for two minutes while seated and resting and the average
resting heart rate was calculated. The participants then jogged in placed for three
minutes. Immediately after jogging, the participants’ heart rates were measured again
for two minutes and the average heart rate after jogging was calculated. The difference
between the average heart rate before and after jogging was also calculated. The
results of the experiment are listed in the following chart.
Female
Average
Resting
Heart
Rate
(bpm)
98
107
109
83
100
75
96
98
103
84
93
116
87
97
93
86
76
97
72
72
72
Female
Average Heart
Rate After
Jogging in
Place for 3
Minutes (bpm)
118
179
158
90
120
97
169
147
141
120
167
158
129
145
135
96
147
133
123
123
125
Change in
Average
Heart
Rate
(bpm)
Male
Average
Resting
Heart Rate
(bpm)
Male Average
Heart Rate
After Jogging
in Place for 3
Minutes (bpm)
Change in
Average
Heart Rate
(bpm)
20
72
49
7
20
22
73
49
38
36
74
42
42
48
42
10
71
36
51
51
53
90
74
83
94
72
87
86
84
70
69
92
84
84
97
100
96
90
74
83
94
72
136
120
142
149
125
99
138
184
160
78
103
128
110
148
118
121
136
120
142
149
125
46
46
59
55
53
12
52
100
90
9
11
44
26
51
18
25
46
46
59
55
53
Conclusion
1. What is the purpose of statistically analyzing study data?
To determine within a set of statistical parameters whether events validate or
invalidate the null hypothesis.
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2. Why should you calculate the mean and standard deviation for sample data?
Mean determine the idea of central tendencies and the deviation determines the
degree of variability in the data around the mean. This tells you a considerable
amount about the population in question.
3. What is the purpose of using a t-test when analyzing study data?
The purpose of using a t-test is to determine if there is a statistical difference
between the two populations in question.
4. How do you decide which type of t-test is the most appropriate for the study data
you want to analyze?
If the populations are the same individuals (paired) or are matched (paired t-test weight loss over time) compared to more independent groups where you are
comparing the means (student t-test – dogs fed on different chow).
5. What does it mean if the t-test shows that the results are not statistically
significant?
If something is not statistically significant we accept the alternative hypothesis –
that there is not difference between the two or more groups tested.
6. What does it mean that the results are not statistically significant for this study?
If there is no significant difference, which indicates that there is no statistical
difference in the measured variables of heart rate between males and females.
7. What do the results of this study mean?
In study number one the analysis (one-tailed t-test) indicates that there is a
statistical difference (p=less than 0.05) indicating males resting heart rates are
slower than female heart rates. For problem three the data analysis (paired-ttest) indicates that that heart rates are significant difference after a period of
exercise (p=less than 0.05) indicating that after exercise heart rate has
increased.
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