Question 1

Which of the following best describes a null hypothesis in experimental design?

Accepted Answer

A statement that there is no effect or difference between groups.

Question 2

When comparing two unpaired groups with non-normally distributed data, which statistical test is most appropriate?

Accepted Answer

Mann-Whitney U test

Question 3

A researcher wants to compare the mean blood pressure between two related groups before and after treatment. Which test should be used?

Accepted Answer

Paired t-test

Question 4

Which of the following is NOT a key feature of a good experimental design?

Accepted Answer

Bias

Question 5

If you have three or more groups and want to compare their means, which statistical test should you use?

Accepted Answer

ANOVA

Question 6

Which formula is used to calculate the mean ($$\mu) of a $$dataset?

Accepted Answer

$$\mu = \frac{\sum x_i}{n}$$

Question 7

A scientist collects data on plant growth and finds the data are not normally distributed. Which measure of central tendency should they use?

Accepted Answer

Median

Question 8

Which of the following best describes the p-value in hypothesis testing?

Accepted Answer

The probability of obtaining the observed results if the null hypothesis is true.

Question 9

A researcher wants to test if a new drug affects heart rate. They measure heart rate before and after administering the drug in the same subjects. Which test should they use if the data are not normally distributed?

Accepted Answer

Wilcoxon signed-rank test

Question 10

Which of the following is a reason to use a control group in an experiment?

Accepted Answer

To provide a baseline for comparison

Question 11

Which statistical test would be most appropriate for comparing the proportions of two categorical variables?

Accepted Answer

Chi-square test

Question 12

What is the main purpose of randomization in experimental design?

Accepted Answer

To minimize bias and confounding variables

Question 13

Which of the following is the correct formula for standard deviation ($$\sigma) of a $$sample?

Accepted Answer

$$\sigma = \sqrt{\frac{\sum (x_i - \mu)^2$}{n-1}}$$

Question 14

A student is analyzing data from an experiment and wants to visually represent the distribution of a single variable. Which graph should they use?

Accepted Answer

Histogram

Question 15

Which of the following is a Type I error in hypothesis testing?

Accepted Answer

Rejecting a true null hypothesis

Question 16

A researcher wants to compare the effect of three different diets on weight loss. Which statistical test should they use?

Accepted Answer

ANOVA

Question 17

Which of the following is NOT a measure of spread in a dataset?

Accepted Answer

Mean

Question 18

In a double-blind experiment, who is unaware of the group assignments?

Accepted Answer

Both the participants and the researchers

Question 19

Which of the following best describes the purpose of replication in scientific experiments?

Accepted Answer

To confirm the reliability and validity of results

Question 20

A scientist wants to test the effect of a fertilizer on plant growth. They measure the height of plants in two groups: one with fertilizer and one without. Which test should they use if the data are normally distributed?

Accepted Answer

Unpaired t-test

Scientific Skills & Statistics in Biology

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