Q: If the mean weight of men is 163.3 kg (SEM = 3.3) and women is 128.6 kg (SEM = 3.0), what is the correct way to test the null hypothesis using the SEM overlap rule?

Add $$2 \times SEM to $$the lower mean and subtract $$2 \times SEM$$ from the higher mean; if the ranges overlap, do not reject the null hypothesis.

Question 1

Which of the following best describes a null hypothesis in a biological experiment?

Accepted Answer

A statement predicting that the treatment will have no effect.

Question 2

In an experiment testing the effect of a drug on worm count in lambs, which is the dependent variable?

Accepted Answer

The number of worms in the GI tract

Question 3

A researcher wants to test if heat shock increases the production of protein X in cells. What is the alternate hypothesis?

Accepted Answer

Heat shock increases the production of protein X.

Question 4

Which formula correctly calculates the sample standard deviation $$s$$ for a group of $$n$$ values $$y_i$$ with mean $$m$$?

Accepted Answer

$$s = \sqrt{\frac{\sum_{i=1}^{n} (y_i - m)^2$}{n-1}}$$

Question 5

If the mean weight of men is 163.3 kg (SEM = 3.3) and women is 128.6 kg (SEM = 3.0), what is the correct way to test the null hypothesis using the SEM overlap rule?

Accepted Answer

Add $$2 	imes SEM to $$the lower mean and subtract $$2 	imes SEM$$ from the higher mean; if the ranges overlap, do not reject the null hypothesis.

Question 6

Which of the following is a positive control in an experiment?

Accepted Answer

A group that receives a treatment known to produce a response

Question 7

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

Accepted Answer

The uncertainty in the estimate of the mean due to sample size

Question 8

Given the data set: 8, 18, 7, 13, 4, what is the mean?

Accepted Answer

10

Question 9

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

Accepted Answer

Rejecting the null hypothesis when it is true

Question 10

A scientist measures the concentration of a hormone in two groups of mice: wild type (WT) and knockout (ARKO) at 3 and 7 months. What are the independent variables?

Accepted Answer

Type of mice (WT and ARKO) and time in months

Question 11

Which of the following is NOT a characteristic of a good scientific question?

Accepted Answer

It cannot be tested or measured

Question 12

If a data set has a large standard deviation, what does this indicate about the data?

Accepted Answer

The data points are spread out over a wide range

Question 13

Which equation correctly calculates the standard error of the mean (SEM) given standard deviation $$s$$ and sample size $$n$$?

Accepted Answer

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

Question 14

In a study, the mean number of worms in the drug group is 30.5 with a standard deviation of 14.1 and $$n=7. $$What is the SEM for this group?

Accepted Answer

$$SEM = \frac{14.1}{\sqrt{7}} \approx 5.33$$

Question 15

A researcher observes that the mean and median of a data set are very different. What does this suggest about the data?

Accepted Answer

The data are likely skewed

Question 16

Which of the following is an example of a parameter in a biological experiment?

Accepted Answer

Concentration

Question 17

In a bar graph comparing two groups, what do the error bars typically represent?

Accepted Answer

The standard deviation or standard error

Question 18

If the p-value in a statistical test is 0.05, what does this mean?

Accepted Answer

There is a 5% chance of rejecting the null hypothesis when it is true

Question 19

Which of the following is a dimension, not a parameter, in scientific measurement?

Accepted Answer

Grams

Statistics and Observations in Biological Science

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