Q: Given the following data set: 5, 5, 4, 6. What is the mean (average)? $\text{Mean} = \frac{\sum x}{n}$

$\text{Mean} = \frac{5+5+4+6}{4} = 5$

Question 1

Which of the following best describes the difference between a bar graph and a line graph?

Accepted Answer

A bar graph is used for discrete variables, while a line graph is used for continuous variables.

Question 2

A researcher reports a p-value of 0.03 for a nutrition intervention study. What does this indicate?

Accepted Answer

There is a 3% chance that the results are due to random chance, suggesting statistical significance.

Question 3

If a 95% confidence interval for a relative risk does NOT include 1, what does this imply?

Accepted Answer

The result is statistically significant.

Question 4

Given the following data set: 5, 5, 4, 6. What is the mean (average)?

$	ext{Mean} = \frac{\sum x}{n}$

Accepted Answer

$	ext{Mean} = \frac{5+5+4+6}{4} = 5$

Question 5

Which of the following is a correct interpretation of error bars on a bar graph?

Accepted Answer

Error bars indicate the uncertainty or variation in the data around the mean.

Question 6

A study finds a relative risk (RR) of 1.5 for developing heart disease in people who consume high amounts of saturated fat compared to those who do not. What does this mean?

Accepted Answer

High saturated fat intake increases the risk of heart disease by 50%.

Question 7

Which of the following is a potential way a graph can be misleading?

Accepted Answer

By omitting the baseline or truncating the y-axis.

Question 8

A 95% confidence interval for a mean is calculated as $\bar{x} \pm 1.96 \frac{s}{\sqrt{n}}$. What does a narrower confidence interval indicate?

Accepted Answer

Greater precision in the estimate of the mean.

Question 9

If a line graph is used to display data where the x-axis is categorical (e.g., types of food), what is the main issue?

Accepted Answer

Line graphs should only be used for continuous data, not categorical data.

Question 10

A study reports a hazard ratio (HR) of 0.7 with a 95% confidence interval of (0.5, 0.9). What does this indicate?

Accepted Answer

The treatment decreases the hazard by 30%, and the result is statistically significant.

Question 11

Which of the following best describes statistical significance?

Accepted Answer

Statistical significance means there is sufficient evidence that the results are unlikely due to random chance.

Question 12

A graph shows the average annual global temperature from 1880 to 2015, but the y-axis ranges from 0 to 120°F. What is the likely effect of this y-axis choice?

Accepted Answer

It minimizes the apparent changes in temperature over time.

Question 13

Which of the following is the correct formula for calculating relative risk (RR)?

$RR = \frac{	ext{Incidence in Exposed}}{	ext{Incidence in Unexposed}}$

Accepted Answer

$RR = \frac{	ext{Incidence in Exposed}}{	ext{Incidence in Unexposed}}$

Question 14

A bar graph displays mercury emission at different times of day with error bars. If the error bars at 11:00 AM and 12:00 PM overlap, what does this suggest?

Accepted Answer

There is likely no statistically significant difference between the means at these times.

Question 15

Which of the following is an example of a misleading graph technique?

Accepted Answer

Cherry picking data points to reinforce a narrative.

Question 16

If a study reports a p-value of 0.08, what is the correct interpretation?

Accepted Answer

There is not enough evidence to reject the null hypothesis at the 0.05 level.

Question 17

Which of the following best describes the relationship between precision and accuracy?

Accepted Answer

Precision refers to how close measurements are to each other, while accuracy refers to how close measurements are to the true value.

Question 18

A meta-analysis finds a relative risk (RR) of 0.85 (95% CI: 0.78, 0.92) for egg consumption and coronary heart disease. What does this mean?

Accepted Answer

Egg consumption decreases the risk of coronary heart disease, and the result is statistically significant.

Question 19

Which of the following is NOT a way to make a graph misleading?

Accepted Answer

Using error bars to show uncertainty.

Scientific Tools for Nutrition Research: Graphs, Statistics, and Risk Analysis

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