Practice Quiz

Question 1

When a researcher is talking about the internal validity of a research study, what is the researcher referring to?

a. confidence in making a cause and effect inference

b. quality of the measurement tools

c. generalizability of the results

Answer 1

a. confidence in making a cause and effect inference

Question 2

When a researcher is talking about the external validity of a research study, what is the researcher referring to?

a. generalizability of the results

b. quality of the measurement tools

c. confidence in making a cause and effect inference

Answer 2

a. generalizability of the results

Question 3

When a researcher is talking about content validity or predictive validity or concurrent validity, what is the researcher referring to?

a. quality of the measurement tools

b. confidence in making a cause and effect inference

c. generalizability of the results

Answer 3

a. quality of the measurement tools

Question 4

Identify the dependent variable(s) in the following journal title.

Peak power output predicts maximal oxygen uptake and performance time in trained cyclists

a. cyclists

b. Peak power output

c. training

d. maximal oxygen uptake and performance time

Answer 4

d. maximal oxygen uptake and performance time

Question 5

Identify the dependent variable(s) in the following journal title.

Physiological effects of constant versus variable power during endurance cycling

a. Physiological effects

b. constant versus variable power

c. cycling

d. endurance

Answer 5

a. Physiological effects

Question 6

Identify the dependent variable(s) in the following journal title.

Relationship of exercise test variables to cycling performance in an Ironman triathlon

a. Ironman triathlon

b. Relationship

c. cycling performance

d. exercise test variables

Answer 6

c. cycling performance

Question 7

Identify the dependent variable(s) in the following journal title.

Metabolic and performance responses to constant-load vs variable-intensity exercise in trained cyclists.

a. constant-load

b. trained cyclists

c. variable-intensity exercise

d. Metabolic and performance responses

Answer 7

d. Metabolic and performance responses

Question 8

Identify the dependent variable(s) in the following journal title.

The effect of carbohydrate ingestion on the motor skill proficiency of soccer players

a. carbohydrate ingestion

b. motor skill proficiency

c. effect

d. soccer players

Answer 8

b. motor skill proficiency

Question 9

Identify the dependent variable(s) in the following journal title.

Acute creatine supplementation and performance during a field test simulating match play in elite female soccer players

a. elite female soccer players

b. performance

c., Acute creatine supplementation

d. field test

Answer 9

b. performance

Question 10

Identify the dependent variable(s) in the dfollowing journal title.

Effects of fluid, electrolyte ingestion on endurance capacity

a. fluid, electrolyte ingestion

b. endurance capacity

c. Effects

Answer 10

b. endurance capacity

Question 11

Identify the dependent variable(s) in the following journal title.

The influence of pre-exercise glucose ingestion on endurance running capacity in older adults

a. pre-exercise glucose ingestion

b. endurance running capacity

c. older adults

d. influence

Answer 11

b. endurance running capacity

Question 12

Identify the dependent variable(s) in the following journal title.

Socioeconomic differences in quality of life in the United States

a. Socioeconomic differences

b. United States

c. quality of life

Answer 12

c. quality of life

Question 13

Identify the dependent variable(s) in the following journal title.

Exercise performance: Effect of initial muscle glycogen concentration with female soccer players

a. initial muscle glycogen concentration

b. female

c. Exercise performance

d.soccer players

Answer 13

c. Exercise performance

Question 14

A researcher was interested in evaluating the effect of exercise dose on individuals’ self-reported quality of life. The researcher recruited from Mechanical Turk (MTurk) only postmenopausal women (n=400) and randomly assigned 100 women to each of 4 dose conditions: control/0, 4, 8, and 12 kilocalories per kilogram body weight per week. After 6 months of exercise the researcher administered each individual a Quality of Life (QOL) questionnaire, and computed a QOL score for each individual with higher scores representing higher QOL.

For this design, what is the independent variable?

a. Gender
b. Menopausal stage
c. Exercise dose
d. Quality of life score

Answer 14

c. Exercise dose

An independent variable is a factor that is believed to affect the dependent variable. Independent variables might also be called explanatory variables or predictor variables.

Question 15

A researcher was interested in evaluating the effect of exercise dose on individuals’ self-reported quality of life. The researcher recruited from Mechanical Turk (MTurk) only postmenopausal women (n=400) and randomly assigned 100 women to each of 4 dose conditions: control/0, 4, 8, and 12 kilocalories per kilogram body weight per week. After 6 months of exercise the researcher administered each individual a Quality of Life (QOL) questionnaire, and computed a QOL score for each individual with higher scores representing higher QOL.

For this design, what is the dependent variable?

a. Gender
b. Menopausal stage
c. Exercise dosage
d. Quality of life score

Answer 15

d. Quality of life score

Dependent variable is the outcome variable or the effect of the independent variable. The dependent variable may be referrd to as the response variable or the criterion variable.

Question 16

A researcher was interested in evaluating the effect of exercise dose on individuals’ self-reported quality of life. The researcher recruited from Mechanical Turk (MTurk) only postmenopausal women (n=400) and randomly assigned 100 women to each of 4 dose conditions: control/0, 4, 8, and 12 kilocalories per kilogram body weight per week. After 6 months of exercise the researcher administered each individual a Quality of Life (QOL) questionnaire, and computed a QOL score for each individual with higher scores representing higher QOL..

What type of sample did the researcher use?

a. Non-probability sample
b. Probability sample

Answer 16

a. Non-probability sample

A probability sample is a sample in which a researcher randomly selects a sample of participants from a population (like a lottery). Note that random selection is not the same as random assignment. Random assignment is when a random process is used to assign participants to the conditions in an experimental design.

Question 17

What effect will selecting only postmenopausal women have on the internal validity of the study design?

a. Strengthen internal validity
b. Weaken internal validity

Answer 17

a. Strengthen internal validity

Internal validity relates to making cause and effect inferences about the effect of an independent variable on a dependent variable. Extraneous and confounding variables weaken internal validity. By narrowing the characteristics of the sample, some confounding variables are controlled.

Question 18

What effect will selecting only postmenopausal women have on the external validity of the study design?

a. Strengthen external validity
b. Weaken external validity

Answer 18

b. Weaken external validity

External validity refers to the generalizability of the results from a study. By narrowing the sample characteristics, external validity would be reduced (e.g., since males were not study it is not possible to draw any conclusions about the effects of exercise dosage on quality of life).

Question 19

If a researcher was looking at the following question: “Do male and female undergraduate college students have the same number of health risk factors?”,

what is the independent variable?

a. Male
b. Female
c. Gender
d. Number of risk factors
e.Undergraduate status

Answer 19

c. Gender

Gender is an independent variable with 2 levels (male, female)

Question 20

A researcher compared the mean number of risk factors for male and female undergraduate students. What statistical technique would be most appropriate for this situation?

a. dependent t-test
b. one group t-test
c. paired t-test
d. independent t-test

Answer 20

independent t-test

Males and females would be considered 2 independent groups, and therefore an independent groups t-test would be appropriate.

Question 21

A researcher reported a t-statistic of 4.50 (p=.003). Using a .05 level of significance, what would be the conclusion of the statistical test?

a. There is a statistically significant difference between males and females in health risks.

b. There is a not a statistically significant difference between males and females in health risks.

Answer 21

There is a statistically significant difference between males and females in health risks

If the p-level from the test of significance is < .05, the difference is statistically significant (.003 is less than .05 so we would reject the null hypothesis of no difference in health risks for males and females and conclude that the difference is more than what we would expect by chance).

Question 22

A researcher calculated Cohen’s d effect size for the male-female comparison on number of health risks. What is your interpretation of a Cohen’s effect size of 1.30?

a. Small effect
b. Moderate effect
c. Large effect
d. A computational error must have been made

Answer 22

c. Large effect

For Cohen’s d, |0.2| is considered small, around |0.5| is considered moderate, and > |0.8| is considered large. Cohen’s d effect size can go from negative infinity to positive infinity. A 1.3 effect size and a -1.3 effect size are equal in strength (you can ignore the negative sign in evaluating the magnitude of an effect).

Question 23

A researcher used an electronic scale to measure participants’ weight. What is the minimum (worse) value for reliability of a measurement instrument?

a. -100
b. -1
c. 0
d. 1
e. 100

Answer 23

0

The minimum reliability for a measurement instrument = 0.

Question 24

A researcher used an electronic scale to measure participants’ weight. What is the maximum (best) value for the reliability of a measurement instrument?

a. -100
b. -1
c. 0
d. 1
e. 100

Answer 24

Perfect measurement reliability = 1.0

Question 25

Person Change in Weight
1 -5 lbs
2 -5 lbs
3 -5 lbs
4 -5 lbs
5 -5 lbs
6 -5 lbs
7 -5 lbs

If the researcher computed the variance of the change in weight, what would be the variance?

a. Negative
b. 0
c. Positive

Answer 25

Since all participants lost 5 lbs (-5), there is no variability in the scores so the variance would = 0.

Question 26

The variance can be negative.
a. True
b. False

Answer 26

b. False

Variance can be 0 (all the scores are the same) or greater than 0 (cannot be negative).

Question 27

Standard deviation can be negative.
a. True
b. False

Answer 27

false

The standard deviation cannot be negative by definition because it measures the dispersion or spread of a set of data points and is calculated as the square root of the variance.

Standard Deviation (σ) = Square Root of [(Sum of Squares of Data Points) divided by (Number of Data Points) minus (Square of the Mean)]

Question 28

Deviation score can be negative.

a. True
b. False

Answer 28

True

A deviation score, often referred to as a Z-score, measures how many standard deviations a particular data point is away from the mean. Therefore, it can be negative.

Question 29

Range can be negative.

a. True
b. False

Answer 29

False

The range of a dataset cannot be negative by definition because the range is a measure of the spread or dispersion of data, specifically the difference between the maximum and minimum values in the dataset.

Question 30

Maximum z-score is +3.0
a. True
b. False

Answer 30

False

Since they are the value different from the mean, Z-scores go from - infinity to positive infinity.

Question 31

If the distribution of raw scores is skewed and you convert the raw scores to z-scores, the distribution will be normal.

a. True
b. False

Answer 31

False

In simple terms, converting raw scores to Z-scores does not magically make the data look like a normal distribution. If your original data is lopsided or skewed, the Z-scores will still show that skewness. Z-scores help us compare and work with data more easily, but they don’t change the shape of the data’s distribution.

Question 32

If a distribution of raw scores is skewed and the scores are converted to z-scores, the mean of the z-scores will equal 0.

a. True
b. False

Answer 32

True

In simple terms, when you convert raw scores to Z-scores, the average of the Z-scores will be 0. This is done to put all the scores on a common scale for easier comparison, with 0 indicating the average or typical value.

Question 33

Which correlation is the strongest?
a. -.90
b. +.85
c. .001
d. .05

Answer 33

a. -.90

numbers closer to +1 or -1 represent the strongest correlation.

Question 34

The correlation between fathers’ education and mothers’ education is .80. Identify a correct interpretation.

a. 80% of the variance in mothers’ education is associated with variance in fathers’ education

b. 20% of the variance in mothers’ education is associated with variance in fathers’ education
Correct Answer

c. 64% of the variance in mothers’ education is associated with variance in fathers’ education

d.36% of the variance in mothers’ education is associated with variance in fathers’ education

Answer 34

64% of the variance in mothers’ education is associated with variance in fathers’ education.

The calculation of the proportion of variance in mothers’ education that is associated with variance in fathers’ education, given a correlation coefficient of 0.80, involves squaring the correlation coefficient. Here’s how the math works:

Start with the correlation coefficient (r), which is 0.80.

Square the correlation coefficient to get the proportion of variance explained:

Variance Explained = r^2

Variance Explained = (0.80)^2

Variance Explained = 0.64

Question 35

A researcher was interested in correlating students’ statistics knowledge with students’ anxiety about statistics. For which group would the correlation of these 2 variables be the strongest?

a. Group A 50 randomly selected doctoral students

b. Group B 50 doctoral students majoring in statistics

Answer 35

a. Group A 50 randomly selected doctoral students

The group with the most variability will produce the largest correlation. Restricting the range on your variables will lower the correlation.

Question 36

In a simple linear regression equation the maximum value for the slope is 1.0.

a. True
b. False

Answer 36

False

In a simple linear regression equation, the slope can be any real number, both positive and negative, and it is not limited to a maximum value of 1.0. The slope represents the change in the dependent variable for a one-unit change in the independent variable, and this change can be any real value depending on the data and the relationship between the variables.

Question 37

Errors of prediction from a linear regression equation can be negative.

a. True
b. False

Answer 37

True

Linear regression errors can be both positive and negative because they represent the differences between the actual data points and the predictions made by the regression model. When the model underestimates the actual values, the errors are positive, and when it overestimates, the errors are negative. The goal of linear regression is to minimize these errors to create the best-fitting line.

Question 38

The standard error of estimate for a linear regression equation can be negative.
a. True
b. False

Answer 38

False

The standard error of estimate in linear regression tells us how much the predictions made by the regression model differ, on average, from the actual data points. It’s like a measure of how wrong the predictions can be. Since it’s about measuring mistakes, it can’t be negative; it’s always a positive number or zero.

Question 39

The variance for a set of scores is 3. If you add 4 points to everyone’s score what will be the variance of the scores?
a. 3
b. 4
c. 16
d. 48
e. You can’t tell

Answer 39

a. 3

Think of variance as a measure of how spread out or varied the scores are in a group. If you add the same number to every score, you’re just shifting all the scores by that amount, like moving them all up or down together. It doesn’t change how spread out they are relative to each other, so the variance stays the same. So, if the variance was 3 before adding 4 points to everyone’s score, it’s still 3 after adding 4 points.

Question 40

The variance for a set of scores is 3. If you multiple everyone’s score by 4 what will be the variance of the scores?
a. 3
b. 4
c. 16
d. 48
e. You can’t tell

Answer 40

d. 48

When you multiply every score in a dataset by a constant, the variance of the dataset changes by the square of that constant. In this case, if you multiply everyone’s score by 4, the variance of the scores will be 16 times larger.

So, if the original variance was 3, after multiplying everyone’s score by 4, the new variance will be:

3 * (4^2) = 3 * 16 = 48

Question 41

If the weight of 500 participants was measured and the mean weight was 250 and the median weight was 105, what would be your interpretation?

a. There must be some extremely low weights

b. There must be some extremely high weights

c. The distribution of weights is bell shaped (normal distribution)

d. This result is impossible

Answer 41

b. There must be some extremely high weights

The mean can be influenced by extreme scores/values. The mean is pulled in the direction of the extreme values. The median is the 50th percentile and will be less affected by these extreme scores.

Question 42

Increasing the sample size in a research study will have what type of effect on the research design?

a. Increase internal validity

b. Increase measurement reliability

c. Increase statistical power

d. Increase measurement validity

Answer 42

c. Increase statistical power

Statistical power is defined as the probability of rejecting the null hypothesis when there is a real difference.

Question 43

To help recruit participants for a research study, a offered participants $100 to participate in a 6 month exercise study. A few participants completed 3 months of the 6 month study and dropped out of the study. How should the researcher handle the financial compensation?

$0. Since the participant didn’t complete the full study, the participant will receive $0 compensation

$50. Since the participant completed half of the study, the $ amount will be prorated

$100. Even though the participant did not complete the full study, the participant will receive $100

Institutional Review Board (IRB) does not permit the payment of research participants

Answer 43

$50. Since the participant completed half of the study, the $ amount will be prorated

When funding is available, financial incentives are often used to recruit participants. Incentives have to be prorated for those who complete only parts of the study. Incentives cannot be so large that they would create undue influence on participants or be coercive.

Question 44

The researchers compared the effect of 3 marathon racing shoes (Nike Zoom Vaporfly 4%, Nike Zoom Streak 6, Adios Boost) on the metabolic cost of running.

How many independent variables are in this study?

a. 1
b. 2
c. 3
d. More than 3

Answer 44

1 independent variable with 3 levels.

Question 45

The researchers compared the effect of 3 marathon racing shoes (Nike Zoom Vaporfly 4%, Nike Zoom Streak 6, Adios Boost) on the metabolic cost of running.

What is the dependent variable in this study?

a. Nike Zoom Vaporfly 4%
b. Nike Zoom Streak 6
c. Adios Boost
d. metabolic cost of running

Answer 45

d. Metabolic cost of running.

Question 46

The researchers concluded that the Nike Zoom Vaporfly made runners run faster.

In reading this statement, what type of validity would be the primary consideration?

a. Ecological validity
b. Internal validity
c. Measurement validity
d. Population validity

Answer 46

b. Internal validity

This is internal validity because the statement is a casual statement; the shoe is what caused the performance increase. You have to determine if there are confounding or extraneous variables.

Question 47

Participants ran 5-min trials at 16 km/h (4.44 m/s) in each shoe condition on a motorized, force-measuring treadmill
(Treadmetrix, Park City, UT, USA) in the Locomotion Lab at the University of Colorado.

In reading this statement what type of validity would be the primary consideration?

a. Ecological validity
b. Internal validity
c. Measurement validity
d. Population validity

Answer 47

c. Ecological validity

Ecological validity is a type of external validity, which is about generalizability. The question to consider as a reviewer of the study is whether the results found in the lab would generalize to running in the real environment

Question 48

“We recruited ten male participants (aged 26.2±4.0 years, mass 63.2±3.1 kg; height 1.77±0.06 m) through personal contacts, running clubs, and social media. Inclusion criteria consisted of: ftting a US men’s size 10 shoe, rearfoot strike pattern, and a recent sub-35-min 10-km (or equivalent) race performance.”

Based on the description of the participants, what effect would the participants have on internal validity?

a. Internal validity would increase (be better)

b. Internal validity would decrease (be worse)

Answer 48

a. Internal validity would increase (be better)

By focusing on a narrow group of participants, confounding variables are controlled thus improving internal validity (confidence in making cause and effect conclusions).

Question 49

“We recruited ten male participants (aged 26.2±4.0 years, mass 63.2±3.1 kg; height 1.77±0.06 m) through personal contacts, running clubs, and social media. Inclusion criteria consisted of: ftting a US men’s size 10 shoe, rearfoot strike pattern, and a recent sub-35-min 10-km (or equivalent) race performance.”

Based on the description of the participants, what effect would the participants have on external validity?

a. External validity would increase (be better)

b. External validity would decrease (be worse)

Answer 49

b. External validity would decrease (be worse)

Generalizability would be reduced since you cannot generalize to females or everyday runners.

Question 50

a runner in the study did a 5-min treadmill run at a specific pace in each shoe.

What type of research design is being used?

a. Between subjects design

b. Within subjects design

Answer 50

b. Within subjects design

If each participant was randomly assigned to only 1 shoe, that would be a between subjects design.

Since participants were tested in each shoe condition, this type of design is a repeated measures design (also called a within subjects design). Participants would be randomly assigned to different orders of the shoes (S1=shoe 1, S2=shoe 2, S3=shoe 3)

S1 S2 S3

S1 S3 S2

S2 S1 S3

S2 S3 S1

S3 S1 S2

S3 S2 S1

Question 51

The 3rd author of the research study is a paid consultant to Nike, Inc. What issue does this raise?

Answer 51

There is a potential conflict of interest (COI). Potential COIs have to be communicated to the Institutional Review Board (IRB). COIs can be managed.

Question 52

A perfect correlation between the amount of sleep and the score on the exam would indicate a causal relationship between these variables.

True
False

Answer 52

False

Question 53

The correlation measures which type of relationship?
a. curvilinear
b. linear
c. cubic
d. quadratic

Answer 53

b. linear

Question 54

Which correlation would indicate an error in calculation?
a. -1.0
b. 0
c. 1.0
d. 100

Answer 54

d. 100

Question 55

Which correlation coefficient would represent the weakest correlation?
a. .05
b. .90
c. -1.0
d. -.50

Answer 55

a. 0.05

Question 56

Which correlation coefficient would represent the strongest correlation?
a. .85
b. .90
c. -1.0
d. -.50

Answer 56

c. -1.0

Question 57

Five middle school students completed the number of pull ups:
7, 14, 4, 4, 6

What is the variance of these scores?
a. 0
b. 3.69
c. 10
d. 13.6

Answer 57

d. 13.6

to calculate variance
1. Calculate the mean (average) of the scores.
2. Subtract the mean from each score to find the deviation of each score from the mean.
3. Square each of these deviations.
4. Find the average of these squared deviations.

Variance (σ²) = Σ(xᵢ - μ)² / N

Question 58

Five middle school students completed the following number of pull ups: 7, 14, 4, 4, 6. What is the range of the number of pull ups?
a. 4
b. 6
c. 7
d. 10

Answer 58

d. 10

Question 59

Five middle school students completed the following number of pull ups: 7, 14, 4, 4, 6. What is the mode for the number of pull ups?

a. 4
b. 6
c. 7
d. 35

Answer 59

a. 4

Question 60

Five middle school students completed the following number of pull ups: 7, 14, 4, 4, 6. What is the median number of pull ups?
a. 4
b. 6
c. 7
d. 35

Answer 60

b. 6

Question 61

Five middle school students completed the following number of pull ups: 7, 14, 4, 4, 6. What is the mean number of pull ups?
a. 4
b. 6
c. 7
d. 35

Answer 61

c. 7

Question 62

It would be appropriate to compute a mean for a group of Social Security numbers.

True or False

Answer 62

False

Mean is not appropriate for a nominal scale

Question 63

It would be appropriate to compute a mean for a group of student ages measured in exact years.

True
False

Answer 63

True

Yes. Mean is appropriate for ratio scale

Question 64

It would be appropriate to compute a median for a group of students ages measured in exact years.

True
False

Answer 64

True

Yes. Median is appropriate for ration scale

Question 65

It would be appropriate to compute a mode for a group of student ages measured in exact years.

True
False

Answer 65

True

Yes. Mode is appropriate for ratio scale.

Question 66

It would be appropriate to compute a standard deviation for a group of student ages measured in exact years.

True
False

Answer 66

True

Question 67

It would be appropriate to compute a mean for the class ranks for group of student.
True
False

Answer 67

False

Question 68

It would be appropriate to compute a median for the class ranks for group of student.

True
False

Answer 68

True

Question 69

It would be appropriate to compute a standard deviation for the class ranks for group of student.

True
False

Answer 69

False

Standard deviation is not appropriate for ordinal scale

Question 70

It would be appropriate to compute a mean for the number of days students visited Campus Recreation.

True
False

Answer 70

True

Question 71

It would be appropriate to compute a standard deviation for the number of days students visited Campus Recreation.

True
False

Answer 71

True

Question 72

The mean test score for the midterm exam is 80%. The median is 94%. What can we say about the shape of the distribution?

a. symmetrical
b. normal
c. skewed left (negatively)
d. skewed right (positive)

Answer 72

c. skewed left (negatively)

Mean is pulled in the direction of the tail. The mean is to the left and left is viewed as the negative direction.

Question 73

The mean test score for the midterm exam is 80%. The median is 80%. What can we say about the shape of the distribution of scores?

a. symmetrical
b. normal
c. negatively skewed (left)
d. positively skewed (right)

Answer 73

a. Symmetrical

Here’s why:

The mean and median are both equal to 80%. In a perfectly symmetrical distribution, the mean and median are equal, and this is the case here.

The term “symmetrical” indicates that the data is evenly distributed on both sides of the center (in this case, the center is 80%). This means that roughly as many students scored above 80% as those who scored below 80%.

Question 74

A researcher computed an effect size comparing the flexibility scores of males and females and found an effect size of +2.0 favoring females. Interpret this effect size of +2.0.

a. small effect
b. moderate effect
c. large effect
d. calculation error

Answer 74

c. Large effect size

Small = .2
Moderate = .5
Large is .8