Deck 6: The Beast of Bias

Question 1

What does independence of data mean?

A) That we must never collect two sets of data from one person.
B) That independent researchers must collect the data.
C) That scores from one participant are free from influences from other participant.
D) That scores in one condition are free from influences from other conditions.

Answer 1

That scores in one condition are free from influences from other conditions.

Question 2

What kind of distribution is the graph below best described as?

A) Positive skew
B) Normal distribution
C) Negative skew
D) Bimodal distribution

Answer 2

Bimodal distribution

Question 3

If a distribution is multimodal, what does this mean?

A) It will not be a normal distribution.
B) The data have been entered incorrectly.
C) It will be a normal distribution.
D) It will have to be checked with a Levene's test.

Answer 3

It will not be a normal distribution.

Question 4

Which of the following tests whether variances are homogeneous?

A) Levene's test
B) Bartlett's test
C) Neither
D) Both

Question 5

Which of the following is not an assumption of a parametric test?

A) Normally distributed data
B) Homogeneity of variance
C) Dependence
D) Independence

Question 6

Which of the following is not a property of a variance ratio?

A) It can be used to demonstrate homogeneity of variances.
B) It is one variance divided by another.
C) It is one variance multiplied by another.
D) It can show the effect of a treatment on several groups.

Question 7

The assumption of homogeneity of variance is met when

A) The variance in one group is twice as big as that of a different group.
B) Variances in different groups are approximately equal.
C) The variance across groups is proportional to the means of those groups.
D) The variance is the same as the interquartile range.

Question 8

What information can you deduce from this histogram?

A) More women than men are diagnosed with Parkinson's disease.
B) The highest incidence of females diagnosed with Parkinson's disease ranges between 75 and 79 years.
C) The highest incidence of females diagnosed with Parkinson's disease ranges between 80 and 84 years.
D) The highest incidence of females diagnosed with Parkinson's disease ranges between 75 and 84 years.

Question 9

What would be the expected effect of transformation to the data gathered in this histogram?

A) The skew will remain the same but significance will be greater.
B) The skew will have increased.
C) The skew will have been reduced.
D)None of the above.

Question 10

In the following histogram, what does its shape suggest?

A) Positive skew
B) Negative skew
C) Normal distribution
D) None of the above

Question 11

If a Kolmogorov-Smirnov test is conducted and the result is significant, what does this mean for the data sample?

A) The data sample is normally distributed.
B) The comparison used in the test is not valid.
C) The data sample is not normally distributed.
D) The test is wrong.

Question 12

Which of the following is not a transformation that can be used to correct skewed data?

A) Log transformation
B) Tangent transformation
C) Square-root transformation
D) Reciprocal transformation

Question 13

What is an outlier?

A) A set of data outside the data file
B) A single score that is very different form the others
C) A score derived from a participant who has lied
D) A variable that cannot be quantified

Question 14

I collected some data about how much buyers of my book liked it (on a scale of 1 = it's utter rubbish to 10 = I never read anything else). I ended up with a sample of 15,467 people. When I looked at the distribution, I found a skew of 1.23 (SE = 0.65). The mean rating was 4.78. Which of the following would be the best way to decide whether the skew is problematic?

A) See if the z-score is bigger than 1.96 or smaller than -1.96.
B) See if the skew is significant at p < .05.
C) Use the Kolmogorov-Smirnov test.
D) None of the above because of the large sample size.

Question 15

What do you deduce about this distribution?

A) The incidence of snoring is greatest among females during middle to old age.
B) Snoring is equally distributed between women and men.
C) The incidence of snoring is greatest in early childhood and again during middle age.
D) None of the above.

Question 16

What statistical test might you use in order to establish whether a distribution is normal and significant?

A) Spearman's test
B) Kolmogorov-Smirnov test
C) t-test
D) None of the above

Question 17

Which of the following are assumptions underlying the use of parametric tests (based on the normal distribution)?

A) The data should be normally distributed.
B) The samples being tested should have approximately equal variances.
C) The data should be at least interval level.
D) All of the above.

Question 18

The Kolmogorov-Smirnov test can be used to test

A) Whether data are normally distributed.
B) Whether group variances are equal.
C) Whether scores are measured at the interval level.
D) Whether group means differ.

Question 19

Which of the following is least affected by outliers?

A) The range
B) The mean
C) The median
D) The standard deviation

Question 20

Why are z-scores used to check for outliers?

A) They standardize scores for a known mean and standard deviation, allowing comparison. *
B) They allow you to allocate letters for missing values.
C) A z-score is an outlier.
D) They standardize scores in order to convert them to values closer to the mean.

Question 21

What is a major constraint about non-parametric tests?

A) They only compare a limited range of situations.
B) They compare a wide range of experimental conditions and not simple situations.
C) They allow for multiple statistical tests to be undertaken.
D) They do not allow for multiple statistical tests to be undertaken.

Question 22

Which of the following is not a transformation technique in SPSS?

A) Square-root transformation
B) Reciprocal transformation
C) Log transformation
D) Unequal transformation

Question 23

What does Levene's test look for?

A) Verification of heterogeneity of variance
B) Verification of homogeneity of variance
C) Verification of significance
D) None of the above