Research Methods & Data Analysis in
Psychology I. Exam #2 University of Iowa
(Voss)
Population ...ANSWER...The total collection of things (e.g., people, trees, etc.) that we
seek information about.
Population Parameter ...ANSWER...Any summary number that describes characteristics
of the entire population.
Parameter of Interest ...ANSWER...Estimated average of what is being measured in a
population. Often characterized by a single Greek letter.
Sample ...ANSWER...A representative collection of those things drawn from the
population.
Descriptive Statistics ...ANSWER...- Describes the data in a way that is more digestible.
- They organize and summarize properties of a data set, and can also visualize them
with graphs.
- *Descriptive statistics* are based only on the data collected in the study.
- They let us examine *Frequencies, Averages, & Variability.*
Inferential Statistics ...ANSWER...Interprets and uses data from a sample to infer
conclusions about a population.
Inference ...ANSWER...The process of drawing conclusions about population
parameters based on a sample taken from the population.
Confidence Intervals ...ANSWER...- *One way to bridge between description and
inference.*
- It gives us a *probable range* of values for the population estimate.
- *Ex:* If our mean is 150 with a 95% confidence interval of 147 to 151, then 95% of all
possible samples should have a mean within this range. So if we repeated our study
100 times then 95 times the mean of the sample will be within this range.
- *Most typical confidence intervals* are: 90%, 95%, 99%
, Hypothesis Testing ...ANSWER...- Test whether your data support or reject your
prediction (test your hypothesis).
- *Hypothesis testing* involves testing your prediction against an alternative possibility.
Null Hypothesis ...ANSWER...- Null Hypothesis testing is very common.
- Null = "nothing"
Socioemotional Selectivity Theory (SEST) ...ANSWER...- As we get older we perceive
we will die soon and we are motivated to regulate emotions so that we emphasize
positive emotion and well-being and tune out negative emotions.
- Therefore we improve our emotional awareness and intelligence with age, and this is
an explanation for increases in well-being during late life despite all the other crap that
happens to our body and mind with age.
*RQ:* Students in research methods last semester had an average of 741
Facebookfriends and 499 Instagram followers. *What kind of statistic is reported above*
A. Descriptive
B. Inferential
C. Neither ...ANSWER...Option A / Descriptive
*RQ:* In last semester's class there was a positive correlation of r=.48 between
Facebook friends and Instagram followers. *What kind of statistic is reported above*
A. Descriptive
B. Inferential
C. Neither ...ANSWER...Option A / Descriptive
*RQ:* A random sample of high school students was selected to take an SAT
preparation course. After completing the course, the mean SAT score for this group of
students was 25 points higher. *What kind of statistic is reported above*
A. Descriptive
B. Inferential
C. Neither ...ANSWER...Option A / Descriptive
*RQ:* I'm interested in estimating how far the average Iowa student can throw a football.
I collect a sample of 500 students from the quad, and another student interested in this
question collects data from a sample of 50 students. Whose confidence interval is likely
larger? *What kind of statistic is reported above*
A. Sample N=500
B. Sample N=50 ...ANSWER...Option A / Sample N=500
Repeated Observations ...ANSWER...- Having multiple observations can reduce
variability for irrelevant factors.
- Overall, items measuring a given construct have similar characteristics.
- Repeated observations can also help with convergent validity.
- Adding items is a good way to increase exhaustivity by ensuring all aspects of the
construct are addressed.
Psychology I. Exam #2 University of Iowa
(Voss)
Population ...ANSWER...The total collection of things (e.g., people, trees, etc.) that we
seek information about.
Population Parameter ...ANSWER...Any summary number that describes characteristics
of the entire population.
Parameter of Interest ...ANSWER...Estimated average of what is being measured in a
population. Often characterized by a single Greek letter.
Sample ...ANSWER...A representative collection of those things drawn from the
population.
Descriptive Statistics ...ANSWER...- Describes the data in a way that is more digestible.
- They organize and summarize properties of a data set, and can also visualize them
with graphs.
- *Descriptive statistics* are based only on the data collected in the study.
- They let us examine *Frequencies, Averages, & Variability.*
Inferential Statistics ...ANSWER...Interprets and uses data from a sample to infer
conclusions about a population.
Inference ...ANSWER...The process of drawing conclusions about population
parameters based on a sample taken from the population.
Confidence Intervals ...ANSWER...- *One way to bridge between description and
inference.*
- It gives us a *probable range* of values for the population estimate.
- *Ex:* If our mean is 150 with a 95% confidence interval of 147 to 151, then 95% of all
possible samples should have a mean within this range. So if we repeated our study
100 times then 95 times the mean of the sample will be within this range.
- *Most typical confidence intervals* are: 90%, 95%, 99%
, Hypothesis Testing ...ANSWER...- Test whether your data support or reject your
prediction (test your hypothesis).
- *Hypothesis testing* involves testing your prediction against an alternative possibility.
Null Hypothesis ...ANSWER...- Null Hypothesis testing is very common.
- Null = "nothing"
Socioemotional Selectivity Theory (SEST) ...ANSWER...- As we get older we perceive
we will die soon and we are motivated to regulate emotions so that we emphasize
positive emotion and well-being and tune out negative emotions.
- Therefore we improve our emotional awareness and intelligence with age, and this is
an explanation for increases in well-being during late life despite all the other crap that
happens to our body and mind with age.
*RQ:* Students in research methods last semester had an average of 741
Facebookfriends and 499 Instagram followers. *What kind of statistic is reported above*
A. Descriptive
B. Inferential
C. Neither ...ANSWER...Option A / Descriptive
*RQ:* In last semester's class there was a positive correlation of r=.48 between
Facebook friends and Instagram followers. *What kind of statistic is reported above*
A. Descriptive
B. Inferential
C. Neither ...ANSWER...Option A / Descriptive
*RQ:* A random sample of high school students was selected to take an SAT
preparation course. After completing the course, the mean SAT score for this group of
students was 25 points higher. *What kind of statistic is reported above*
A. Descriptive
B. Inferential
C. Neither ...ANSWER...Option A / Descriptive
*RQ:* I'm interested in estimating how far the average Iowa student can throw a football.
I collect a sample of 500 students from the quad, and another student interested in this
question collects data from a sample of 50 students. Whose confidence interval is likely
larger? *What kind of statistic is reported above*
A. Sample N=500
B. Sample N=50 ...ANSWER...Option A / Sample N=500
Repeated Observations ...ANSWER...- Having multiple observations can reduce
variability for irrelevant factors.
- Overall, items measuring a given construct have similar characteristics.
- Repeated observations can also help with convergent validity.
- Adding items is a good way to increase exhaustivity by ensuring all aspects of the
construct are addressed.
