Question 1

Which of the following best describes the purpose of a chi-square ($\chi^2$) test in biological experiments?

Accepted Answer

To compare observed and expected frequencies to test a hypothesis

Question 2

A student flips a coin 160 times and observes 90 heads and 70 tails. What is the expected number of heads and tails if the coin is fair?

Accepted Answer

80 heads, 80 tails

Question 3

Which formula is used to calculate the chi-square ($\chi^2$) value?

Accepted Answer

$\chi^2 = \sum \frac{(O - E)^2}{E}$

Question 4

In a chi-square test, what does it mean if your calculated $\chi^2$ value is LESS than the critical value from the chi-square table?

Accepted Answer

The observed and expected values are not significantly different; fail to reject the null hypothesis.

Question 5

Which of the following is NOT considered evidence for evolution?

Accepted Answer

Analogous structures

Question 6

Why are analogous structures NOT considered evidence of shared ancestry?

Accepted Answer

They result from convergent evolution, not common descent.

Question 7

A researcher wants to test whether the distribution of seed types eaten by i’iwi birds matches what is expected. Which statistical test should they use?

Accepted Answer

Chi-square test

Question 8

If you have 5 categories in your data, what is the degrees of freedom ($df$) for your chi-square test?

Accepted Answer

$df = 4$

Question 9

Which of the following is a correct hypothesis statement for a chi-square test involving pea plant phenotypes?

Accepted Answer

If pea plants are grown under identical conditions, then the observed phenotype ratios will match the expected ratios because genetic inheritance follows Mendelian laws.

Question 10

Which scenario would require you to reject the null hypothesis in a chi-square test?

Accepted Answer

Your calculated $\chi^2$ value is greater than the critical value at your chosen significance level.

Question 11

Which of the following is an example of a homologous structure?

Accepted Answer

The forelimbs of humans and bats

Question 12

A scientist collects data on the number of sharks caught in Kaneohe Bay over several months. Which type of data is this?

Accepted Answer

Discrete data

Question 13

Which of the following statements about the null hypothesis in a chi-square test is correct?

Accepted Answer

It states that there is no significant difference between observed and expected values.

Question 14

In a real-world scenario, why might a biologist use a chi-square test when studying animal coloration in a population?

Accepted Answer

To determine if the observed frequencies of different color morphs match the expected genetic ratios

Question 15

Which of the following is a multi-step process required to perform a chi-square test?

Accepted Answer

Calculate expected values, compute $\chi^2$ using $\chi^2 = \sum \frac{(O - E)^2}{E}$, determine degrees of freedom, and compare to the critical value.

Question 16

Which of the following would be a plausible reason for a chi-square test to show a significant difference between observed and expected values in a genetics experiment?

Accepted Answer

There is a non-Mendelian inheritance pattern affecting the results.

Question 17

Which of the following is a correct interpretation if the chi-square test results in a $p$-value less than 0.05?

Accepted Answer

There is a statistically significant difference between observed and expected values.

Question 18

Which of the following is an example of a real-life application of the chi-square test in biology?

Accepted Answer

Testing whether the distribution of blood types in a population matches expected genetic frequencies

Chi-Square Analysis and Evidence for Evolution: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards