Question 1

Which sampling method is illustrated by selecting every 3rd person from a line of people, as shown in the first image?

Accepted Answer

Systematic sampling

Question 2

In the second image, women and men are grouped separately and then individuals are selected from each group. What sampling method does this represent?

Accepted Answer

Stratified sampling

Question 3

Refer to the third image. Interviewing all voters in randomly selected precincts is an example of which sampling method?

Accepted Answer

Cluster sampling

Question 4

According to the flowchart in the fourth image, which type of observational study collects data by looking back in time?

Accepted Answer

Retrospective study

Question 5

In the fifth image, all women are treated and all men receive a placebo. What is the main flaw in this experimental design?

Accepted Answer

It does not control for confounding variables between genders.

Question 6

The sixth image shows randomly selected subjects from both genders receiving treatment or placebo. What experimental design is this?

Accepted Answer

Completely randomized design

Question 7

In the seventh image, men and women are separated into blocks, and then randomly selected individuals from each block are treated. What is this design called?

Accepted Answer

Randomized block design

Question 8

The eighth image shows 'before' and 'after' measurements for the same individuals. What experimental design does this illustrate?

Accepted Answer

Matched pairs design

Question 9

The ninth image is a time-series graph. What is the main purpose of a time-series graph?

Accepted Answer

To show trends in data over time

Question 10

The tenth image is a Pareto chart. What is a key feature of a Pareto chart?

Accepted Answer

Bars are arranged in descending order of frequency

Question 11

The eleventh image is a scatterplot. What does a scatterplot best illustrate?

Accepted Answer

The relationship between two quantitative variables

Question 12

The twelfth image is a pie chart. What is a limitation of using a pie chart for data analysis?

Accepted Answer

It is difficult to compare similar-sized categories

Question 13

The thirteenth image is a pictograph. What is a common problem with pictographs?

Accepted Answer

They can exaggerate differences by using area or volume

Question 14

The fourteenth image shows two bar graphs with different vertical axis starting points. What is the risk of using a nonzero vertical axis?

Accepted Answer

It exaggerates differences between groups

Question 15

The fifteenth image is a pictograph of phone records. Why might this pictograph be misleading?

Accepted Answer

The size of the images exaggerates the difference in values

Question 16

Given the formula in the sixteenth image, what is the mean of the dataset $$50, 25, 75, 35, 50, 25, 30, 50, 45, 25, 20$$?

Accepted Answer

$$\frac{430}{11} = 39.1$$

Question 17

According to the measures of center diagram, which measure is most appropriate for ordinal data?

Accepted Answer

Median

Question 18

Refer to the skewness diagrams. In a distribution skewed to the right (positively skewed), which is the correct order of mean, median, and mode?

Accepted Answer

Mode \u003c Median \u003c Mean

Question 19

Given the dataset in the eighteenth image, what is the range?

Accepted Answer

$$55$$

Question 20

According to the Empirical Rule diagram, what percentage of data falls within two standard deviations of the mean in a normal distribution?

Accepted Answer

$$95\%$$

Foundations of Statistics: Data, Sampling, Graphs, and Measures of Center & Variation

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