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Faculty of Health, Medicine and Life Sciences1.1.1 Seminar 1.2 assignments
Don’t forget watching the videos!
Statistical concepts to be discussed: Z-scores, Pearson correlation, R-square, regression
model, regression line
Problem 1
When a distribution of raw scores is converted to z-scores, the shape (i.e.
the type) of the distribution…
a. Flattens out to a uniform distribution
b. Approaches a normal distribution
c. Is unpredictable
d. Remains the same
Answers:
The z-distribution always has the same shape as the raw score
distribution. When raw scores are transformed into z-scores, the mean will
always be 0. When raw scores are transformed into z-scores, the standard
deviation will always be 1.
Problem 2
If the dots on a scatterplot generally extend from the bottom left to the
upper right of the diagram but are very widely spread out, the researcher
would report the correlation:
a. As strong and positive
b. As weak and positive
c. As strong and negative
d. As close to zero
Answer:
If the dots extend from the bottom left to the upper right of the diagram,
it is a positive linear relation. If it is close to zero, the dots are on the line
itself so close to each other. The correlation becomes stronger if the
distance between the dots become smaller. If the dots are widely spread
out, the correlation becomes weaker.
Problem 3
What is the minimum level of measurement to calculate Pearson’s r
correlation coefficient?
a. Nominal
BBS1003 Syllabus 2020-2021 202020
, Faculty of Health, Medicine and Life Sciences
b. Interval
c. Ordinal
d. Ratio
Answer:
For a Pearson correlation, each variable should be continuous so nominal
and ordinal are not an option. It also needs dispersion and differences.
Problem 4
What is the predicted value (theoretical mean) of Y when X = 10 using the
regression equation: Y = 30 – 1.2 X
a. 18
b. 28.8
c. 10
d. Cannot calculate without additional information
Answers:
X=10.
Y= 30 - (1.2 * 10)
Y= 18
Problem 5
Correlations (using Pearson product-moment correlation coefficient) may
be uninterpretable and inappropriate if the two variables…
a. Are inversely related
b. Are interval level
c. Have a nonlinear relationship
d. Come from a sample n < 20
Answers:
Without a linear relationship, there is no correlation.
BBS1003 Syllabus 2020-2021 212121
, Faculty of Health, Medicine and Life Sciences
Problem 6
The difference between a predicted Y score and an actual observed Y
score is known as the …
a. All of the answers are correct.
b. Imperfection coefficient
c. Error ratio.
d. Residual.
Answers:
Error ratio is also sometimes used.
Problem 7
If the dots on a scatterplot are spread out randomly, the researcher would
report the correlation as:
a. Strong and positive
b. Weak and positive
c. Close to zero
d. Weak and negative
Answers:
If the dots in the scatterplot are spread out randomly, there is no linear
correlation. So strong, weak, positive and negative are out of context. The
researcher would hence report the correlation as close to zero.
Problem 8
Which of the following is an impossible value for R 2 ?
a. 0.16
b. 1.10
c. 0.36
d. 0.00
Answers:
The values of R2 range between 0 and 1.
Problem 9
Which of the following illustrates a negative correlation?
a. The more often a person exercises, the more muscle mass he/she
will accumulate.
b. As a person writes less, the quality of his/her writing decreases.
c. The less often a person gets sick, the less sick days he/she would
need to take off work.
d. The more often a person visits the dentist, the fewer cavities he/she
has.
Answers:
BBS1003 Syllabus 2020-2021 222222
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