Question 1

Data cleaning is only necessary when you did not collect the data.

Accepted Answer

Data cleaning is necessary regardless of who collected the data, as it ensures accuracy, consistency, and completeness of the data for analysis.

Question 2

When grouping variables, intervals should be exhaustive and mutually exclusive.

Accepted Answer

Grouping variables into intervals requires that every possible value is included (exhaustive) and that no value falls into more than one interval (mutually exclusive) to ensure accurate and meaningful categorization.

Question 3

Skewness is an appropriate measure when describing a nominal variable.

Accepted Answer

Skewness measures the asymmetry of the distribution of values in a dataset, which is applicable only to ordinal or continuous data, not nominal variables.

Question 4

The median is an inappropriate statistic for variables measured at the nominal level.

Accepted Answer

The median requires data that can be ordered or ranked, which is not possible with nominal level variables that categorize data without a natural order.

Question 5

The interquartile range measures the difference between the first and fourth quartiles in a distribution.

Accepted Answer

The interquartile range measures the difference between the third (75th percentile) and first (25th percentile) quartiles in a distribution.

Question 6

In a monotonic relationship, the value of cases consistently increases on one variable as the value of cases increases on the other variable.

Accepted Answer

In a monotonic relationship, as the value of one variable increases, the value of the other variable consistently increases (or consistently decreases), but not necessarily at a constant rate.

Question 7

If the value of gamma is +1, then the variables are perfectly associated with each other.

Accepted Answer

A gamma value of +1 indicates a perfect positive association between variables, meaning as one variable increases, the other variable also increases consistently.

Question 8

Specification is when the original relationship is stronger under some condition(s) of a third variable and weaker under others.

Accepted Answer

Specification refers to a situation in multivariate analysis where the relationship between two variables changes strength or direction under different conditions of a third variable, indicating that the effect of the original relationship is contingent upon the levels or values of this third variable.

Question 9

The highest value in a distribution minus the lowest value in the distribution will provide the central tendency.

Accepted Answer

The highest value minus the lowest value in a distribution provides the range, not the central tendency. Central tendency is typically measured by the mean, median, or mode.

Question 10

Standard deviation is the preferred measure of variation.

Accepted Answer

Standard deviation is a more comprehensive measure of variation than range or variance, as it takes into account the distribution of data points around the mean.

Question 11

Descriptive statistics estimate the degree of confidence that can be placed in generalizations for a sample and for the population from which the sample was selected.

Accepted Answer

Descriptive statistics summarize and describe the main features of a data set, including measures of central tendency and variability, without making inferences or generalizations about the population from which the sample was drawn.

Question 12

A researcher reviews a distribution of a variable and notes that in the distribution the cases cluster to the right and the left tail of the distribution is longer than the right tail. This distribution is negatively skewed.

Accepted Answer

In a negatively skewed distribution, the majority of the data points are clustered towards the right side of the distribution, resulting in a longer left tail. This description matches the scenario provided.

Question 13

The Base N in a frequency distribution refers to the total number of cases.

Accepted Answer

The Base N in a frequency distribution indeed refers to the total number of cases or observations that are being analyzed or reported.

Question 14

In order to calculate measures of variation, the data must be at the ordinal or ratio level.

Accepted Answer

Measures of variation, such as range, variance, and standard deviation, require numerical data that can be ordered and compared. Ordinal and ratio level data meet these criteria, as they allow for meaningful comparisons of differences between data points.

Question 15

A researcher finds that as age increases, the number of crimes committed decreases. The relationship between the two variables would be classified as positive.

Accepted Answer

The relationship described is negative because as one variable (age) increases, the other variable (number of crimes committed) decreases.

Question 16

Measures of central tendency include the mode, median, and the variance.

Accepted Answer

Measures of central tendency include the mode, median, and the mean, not the variance. Variance is a measure of dispersion.

Question 17

Measures of dispersion include the range, variance, and the standard deviation.

Accepted Answer

Measures of dispersion are statistical tools used to describe the spread or variability within a data set, and they include the range, variance, and standard deviation among others.

Question 18

The range is the most mathematically complicated measure of dispersion.

Accepted Answer

The range, calculated as the difference between the maximum and minimum values in a dataset, is one of the simplest measures of dispersion, unlike variance or standard deviation which involve more complex calculations.

Question 19

The interquartile range avoids the problem created by unusually high or low scores in a distribution.

Accepted Answer

The interquartile range (IQR) measures the spread of the middle 50% of data, thus it is not affected by extreme values (outliers) in either tail of the distribution.

Question 20

Quartiles split a variable's distribution into three equal groups of cases.

Accepted Answer

Quartiles split a variable's distribution into four equal parts, not three.

Quiz 14: Analyzing Quantitative Data