Question 1

Which of the following best describes a null hypothesis ($$H_0) in an $$experiment testing the effect of a new fertilizer on plant growth?

Accepted Answer

There will be no effect of the fertilizer on plant growth.

Question 2

A researcher collects the heights of all students in a biology class. What type of variable is 'height'?

Accepted Answer

Continuous variable

Question 3

Which formula correctly represents the calculation of the population mean ($$\mu$$)?

Accepted Answer

$$\mu = \frac{\sum_{i=1}^{N} x_i}{N}$$

Question 4

If a dataset contains the values 2, 4, 4, 5, 7, what is the mode?

Accepted Answer

4

Question 5

Which measure of central tendency is most appropriate when a dataset is highly skewed due to outliers?

Accepted Answer

Median

Question 6

Given the following jaw lengths (in mm): 109, 80, 79, 103, 99, calculate the sample mean ($$\bar{x}).$$

Accepted Answer

94

Question 7

Which formula is used to calculate the sample standard deviation ($$s$$)?

Accepted Answer

$$s = \sqrt{\frac{\sum_{i=1}^{n} (x_i - \bar{x})^2$}{n-1}}$$

Question 8

A sample has a mean of 165.46 and a standard deviation of 7.62. What is the value one standard deviation above the mean?

Accepted Answer

173.08

Question 9

What does the standard error of the mean (SEM) quantify?

Accepted Answer

The uncertainty in the estimate of the mean

Question 10

Which formula is used to calculate the standard error of the mean (SEM)?

Accepted Answer

$$SEM = \frac{s}{\sqrt{n}}$$

Question 11

A researcher wants to compare the mean body mass of newts before and after a treatment on the same individuals. Which statistical test should they use?

Accepted Answer

Paired samples t-test

Question 12

Which of the following is a categorical variable?

Accepted Answer

Color of hair

Question 13

If the p-value from a t-test is 0.03, what does this indicate about the null hypothesis?

Accepted Answer

There is evidence to reject the null hypothesis at the 0.05 significance level.

Question 14

Which formula is used to calculate the t-statistic for comparing two independent sample means?

Accepted Answer

$$t = \frac{\bar{x}_1 - \bar{x}_2}{\sqrt{\frac{s_1$^2}{n_1$} + \frac{s_2$^2}{n_2$}}}$$

Question 15

A dataset has a right-skewed distribution. Which measure of central tendency is likely to be the largest?

Accepted Answer

Mean

Question 16

Which of the following best describes a discrete variable?

Accepted Answer

Number of students present in a class

Question 17

If you sample 15 individuals from a population of 50, what can you say about your estimate of the population mean?

Accepted Answer

It is a good approximation of the true mean.

Question 18

Which of the following is NOT a type of inferential statistical test?

Accepted Answer

Mode calculation

Question 19

What is the main difference between standard deviation (SD) and standard error of the mean (SEM)?

Accepted Answer

SD measures spread of data; SEM measures uncertainty in the mean estimate.

Question 20

If you want to know whether the average birth weight in a local population differs from the national average of 7 lbs, which test should you use?

Accepted Answer

One sample t-test

L13 Statistics and Experimental Design in Biology: Central Tendency, Dispersion, and Inferential Tests

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