Principles of Statistics and Research Design
What is the mode for the following sample of n = 8 scores? Scores: 0, 1, 1, 1, 2, 2, 3, 3
1
A skewed distribution typically has ____ tail(s) and a normal distribution has ____ tail(s).
1,2
What is the value of SS (sum of squared deviations) for the following sample? Sample: 1, 1, 1, 3
12
What is the total number of scores for the distribution shown in the following table? X f 4 3 3 3 5 2 4 1 2
14
What is the value of ΣX2 for the following scores? Scores: 1, 0, 2, 4
21
What is the median for the following set of scores? Scores: 1, 2, 6, 11, 17
6
What is the value of the median for the following set of scores? Scores: 1, 3, 4, 6, 7, 8, 12, 23
6.5
What is the value of (ΣX)2 for the following scores? Scores: 1, 5, 2
64
If a set of exam scores forms a symmetrical distribution, what can we conclude about the students' scores?
About 50% of the students had high scores and the rest had low scores.
A researcher conducts an experiment to determine whether moderate doses of St. John's wort have any effect on memory for college students. For this study, what is the independent variable?
The amount of St. John's wort given to each participant
Which description provides an example of a discrete variable?
The gender of each student in a psychology class
A good hypothesis must ____.
allow for all variables to be measured
If a variable can be divided into an infinite number of fractional parts, then it is a(n) ____ variable.
continuous
An explanation is empirical if it is based on ____.
evidence of the senses
If sample variance is computed by dividing SS by df = n - 1, then the average value of the sample variances from all the possible random samples will be ____ the population variance.
exactly equal to
A hypothesis is a ____ statement and a prediction is a ____ statement.
general, specific
For a negatively skewed distribution with a mean of M = 20, what is the most probable value for the median?
greater than 20
If you are a psychologist embarking on a research study, what should you do first?
identify an idea and search the literature to form the research question
A person who buys a lottery ticket because s/he just feels lucky is using the method of ____.
intuition
Which method of acquiring knowledge is being used by students who are learning from teachers and textbooks?
method of authority
A researcher measures eye color for a sample of n = 50 people. Which measure of central tendency would be appropriate to summarize the measurements?
mode
In the simplest experimental study, ____.
one variable is measured and two groups are compared
Using letter grades (A, B, C, D, and E) to classify student performance on an exam is an example of measurement on a(n) ____ scale of measurement.
ordinal
A researcher uses an anonymous survey to investigate the study habits of American college students. The entire group of American college students is an example of a ____.
population
Combat veterans may be diagnosed with post-traumatic stress disorder (PTSD). You wonder about the best way to treat PTSD. This is an example of getting research ideas from ____.
practical problems
An empirical journal article is an example of a ____ source.
primary
The discussion section of a research article typically ____.
provides interpretation of the findings
Your PsycINFO search has yielded several hundred articles. The most efficient next step is to ____.
read the abstracts to determine if you want to read the articles
A sample of n = 9 scores has a variance of s2 = 144. What is the standard deviation for this sample?
s=12
A researcher is interested in the eating behavior of rats and selects a group of 25 rats to be tested in a research study. The group of 25 rats is an example of a ____.
sample
Although a research study is typically conducted with a relatively small group of participants known as a ____, most researchers hope to generalize their results to a much larger group known as a ____.
sample, population
When you "know" that you do not want to eat chocolate-covered crickets, even when everyone around you says that they taste great, your decision is based on the method of ____.
tenacity
A limitation of using the method of empiricism is that ____.
the process can be time consuming and often risky
A potential drawback of secondary sources is that they ____.
typically do not contain detailed information about any specific study