1. Evaluating Data in Research
Statistics
Evaluating Data in Research
AP exam has 3-5 questions
This is what makes Psych more scientific – makes things quantifiable.

2. Percentile Ranks
Joey finished at the 74th percentile on his EOC Algebra test.
74th percentile means
Above 74% of test takers
Actual #75, there is no 100th percentile

3. Central Tendencies
A measure of central tendency is a single score that represents a whole set of scores.
Mean –
Average
Mean most easily skewed by outliers (extreme numbers)
Median
Middle value (midpoint, or 50th percentile)
(Place in sequential order and find middle number)
Mode
Most frequently occurring score

4. Measures of variability
RANGE: difference between the highest and lowest scores (can be deceptive due to outliers)
MEAN 7 6 5 4 3 2 1

5. measures of variability
STANDARD DEVIATION: how much any score differs from the average, or mean score
MEAN
+1 sd
-1 sd 7 6 5 4 3 2 1

6. The more spread out the scores, the larger the STANDARD DEVIATION.
MEAN
+1 sd
-1 sd 7 6 5 4 3 2 1

7. Bell Curve A graph of normal distribution
1 SD = 68% of scores
2 SD = 95% of scores
3 SD = 99.7% of scores

8. Weighing the odds… Which player do you play? 2 High School punters
Kicker A:
mean distance: 39.8 yds
Standard deviation: yds.
Kicker B:
mean distance: 34.5 yds.
Standard deviation: + 4 yds.
Which player do you play?
Player B – team will know where to run

9. Statistical Significance
When is a study’s data significant?
When there is a significant difference between the results (data) for the control group and experimental group.
When the data is reliable (consistent)

10. Statistical Practice…
1. What is the mean of the following distribution of scores: 2, 3, 7, 6, 1, 4, 9, 5, 8, 2?
A. 5
B. 4
C. 4.7
D. 3.7
E. 6
Answer: c

11. Statistical Practice…
What is the median of the following distribution of scores: 1, 3, 7, 7, 2, 8, 4?
a. 1
b. 2
c. 3
d. 4
Answer: d

12. Statistical Practice…
What is the mode of the following distribution: 8, 2, 1, 1, 3, 7, 6, 2, 0, 2?
a. 1
b. 2
c. 3
d. 7
Answer: b

13. One for the record…
Seven members of a Girl Scout troop report the following individual earnings from their sale of candy: $4, $1, $7, $6, $8, $2, and $7. In this distribution of individual earnings:
The mean is equal to the mode and equal to the median
The mean is less than the mode and equal to the median
The mean is equal to the mode and greater than the median
The mean is greater than the mode and greater than the median
The mean is less than the mode and less than the median
Mean=5, median=6, mode=7
Answer=e

14. Ethics in Research APA Ethical Guidelines Informed Consent
No harm to patients
Confidentiality
Debriefing

15. Animal Testing Statistics to consider…
30,000,000 animals used for research each year constitutes 1% of animals killed each year to eat.
200,000 dogs and cats researched annually / animal shelters euthanize 50x that each year
Is it morally acceptable to place the well- being of humans above other animals regarding research?