Latest Quiz
What measurement level is the variable "military rank"? ANS Ordinal
Rationale: Military rank does not have a true zero or equal intervals, but the categories can be put in order:
private, corporal, sergeant, and master sergeant
True or False
A histogram would be a good way to show the distribution of ethnicity among the participants of a study.
ANS •False
•Rationale: Ethnicity is a nominal level variable. Histograms are used for interval and ratio level variables. A
frequency table or a bar chart would be a better choice.
•What would be an appropriate measure of central tendency to use when looking at height of children at age 5?
ANS •All of these
•Rationale: Height is a ratio level variable (true zero), so all of these are appropriate to use.
The standard deviation of the numbers 3, 8, 12, 17 and 25 is 7.56. What is the standard deviation if each of the
five numbers is increased by 2 ANS The standard deviation stays the same
Rationale:If each number is increased by 2, then the mean is also increased by 2.Thevalues of the differences,
therefore, remain the same as before; and so the value of the standard deviation is also the same as before
•The standard deviation of the numbers 3, 8, 12, 17 and 25 is 7.56. What is the standard deviation if each of the
five numbers is multiplied by 2. ANS The standard deviation is multiplied by 2
•Rationale: If each number is multiplied by 2, then the mean is also multiplied by 2. The values of the
differences, therefore, are also multiplied by 2.
•The probability of drawing a card that is an "ace" out of a standard deck of 52 cards is an example of what
type of probability? ANS Marginal
There are four aces in the deck. The probability is simply 4/52 = 0.07692
,•Each of the letters of the word MISSISSIPPI are written on separate pieces of paper that are then folded, put
in a hat, and mixed thoroughly. One piece of paper is chosen (without looking) from the hat. What is the
probability it is an I? ANS •There are 4 I's in the word MISSISSIPPI, so the number of ways it can happen
= 4.There are 11 letters altogether in the word MISSISSIPPI, so the total number of outcomes = 11.So the
probability the letter chosen is an I = 4/11 = .36
There are 10 counters in a bag: 3 are red, 2 are blue and 5 are green. The contents of the bag are shaken before
Mary randomly chooses one counter from the bag. What is the probability that she doesn't pick a red counter?
ANS There are 7 counters that are not red: 2 blue and 5 green.
The number of ways it can happen = 7The total number of outcomes = 10Therefore, the probability of not
picking a red counter = 7/10 = .70
•95% of students at a school are between 1.1m and 1.7m tall.
•Assuming this data is normally distributed can you calculate the mean and standard deviation? ANS •The
mean is halfway between 1.1m and 1.7m. So Mean = (1.1m + 1.7m) / 2 = 1.4m
•95% is 2 standard deviations either side of the mean (a total of 4 standard deviations).
•
•If a value has a positive Z-score, its percentile rank is
A. Above 50
B. Below 50
C. Exactly 50
D. There is not enough information to tell ANS Above 50
Rationale: Those points with a positive Z-score have a percentile rank of greater than 50.
Which type of hypothesis is the following statement?
People who are immunized against the flu will be less likely to contract the flu than those who are not
immunized. ANS Directional hypothesis
Rationale: This hypothesis states that a relationship between immunization and contracting the flu is
expectedand alsostates the direction of that relationship
If there is, in fact, a relationship between immunization and contracting the flu, but the researcher concludes
there is no relationship, what type of error have they committed? ANS Type II Error
,Rationale: A type II error is when we say that there is no relationship between the variables, but one really does
exist.
True/False
If the difference between two groups is large, we can say that it is statistically significant even if our computed
p-value is not less than the α-level that we set for the study. ANS False
Rationale: Statistical significance is defined by our computedp-value and our presetα-level
The variable "height in inches" is a clear example of which of the following types of variable? ANS
Characteristic of interest
Rationale: The variable "height in inches" is interval or ratio. It could be either a dependent variable or an
independent variable
Consider the following question: Do adults who are immunized against the flu lose fewer days at work than
those who are not immunized?
What is the grouping variable and what is the dependent variable? ANS B. Immunization status is the
grouping variable
A. Days lost at work is the dependent variable
Rationale: Immunization status has two categories (immunized vs. not immunized) and defines the two groups.
Days lost at work is a ratio variable, andvary according to immunization status.
True/False
Paired data must always come from pretest/posttest designs. ANS False
Rationale: Paired data can also come from studies with cases and matched controls (such as twin studies).
•A study compares calorie consumption in a group of 15 teenagers who are on a sports team with a comparison
group of 19 teenagers who do not play sports.What type of data is this? ANS Unmatched data
Rationale: 15 teens in one group, 19 in the other. We are not told of any matching criteria. In a matched design,
there would be the same number of participants in each group, and we would be told what the matching criteria
were. This is a simple example of a study with an unmatched comparison group.
How can we tell which means are different in an ANOVA? ANS Post hoc tests
Rationale: Post hoc tests are used to tell us which means are different in ANOVA test.
, True/False
The Kruskal-Wallis H-test can be used with paired data. ANS False
The Kruskal-Wallis H-test has fewer assumptions than one-way ANOVA, but the groups still have to be
independent of one another.
•How many groups are defined by the variables gender (2 levels) and smoking status (never, former smoker,
current smoker)? ANS 6
Rationale: The total number of groups defined is the number of levels in the first factor times the number of
levels in the second factor
True or False
Post-hoc tests are necessary for dichotomous variables. ANS False
Rationale: Dichotomous variables only have two groups. Post-hoc tests are used to see which means differ
from one another in cases where there are three or more groups.
In the hypothesis "There is a difference between elderly study participants with sedentary lifestyle and elderly
study participants with active lifestyle in the elders' perceived level of self-efficacy," which is the independent
variable?
A. Age
B. Elderly study participants
C. Perceived self-efficacy
D. Type of lifestyle ANS Answer:
Type of lifestyle
Rationale:
Sedentary versus active lifestyle is the presumed influence on level of self-efficacy.
Which of the following is NOT a source for the development of a research problem?
A. Codes of ethics
B. Theories