# Biology

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### Biology Basics: Systemic Circulation

Systemic circulation brings oxygenated blood around to all your body’s cells. Here is a description of how blood moves through this pathway (see the figure):

### Biology Topics to Study for the Miller Analogies Test (MAT)

Science and math aren't the most prevalent topics on the MAT, but they are tested. The biology topics listed here will help you prepare for the MAT by exposing you to the major subjects in the biology

### The Bootstrap Method for Standard Errors and Confidence Intervals

You can calculate the standard error (SE) and confidence interval (CI) of the more common sample statistics (means, proportions, event counts and rates, and regression coefficients). But an SE and CI exist

### Two Views of Probability

Two quite different ideas about probability have coexisted for more than a century. These probability approaches, which differ in several important ways, are as follows:

### Trying the Simulation Approach in Statistical Analysis

Modern statistical software makes it easy for you to analyze your data in most of the situations that you’re likely to encounter (summarize and graph your data, calculate confidence intervals, run common

### Model Building with Stepwise Regression

One of the reasons (but not the only reason) for running a multiple regression analysis is to come up with a prediction formula for some outcome variable, based on a set of available predictor variables

### 10 Names Every Biostatistician Should Know

Biostatistics, in its present form, is the cumulative result of four centuries of contributions from many mathematicians and scientists. Some are well known, and some are obscure; some are famous people

### Estimating Sample-Size Requirements with a Handy Calculator

While many programs, apps, and web pages are available to perform power and sample-size calculations, they aren’t always easy or intuitive to use. Because spreadsheets like Excel are readily available

### Estimating Sample Size for Correlation Tests in Biostatistics

For a correlation test in biostatistics (such as the Pearson or Spearman test), pick the scatter chart that looks like an important amount of correlation. Each chart shows the value of

### Sample Size Estimation for Unpaired Student t Tests in Biostatistics

In biostatistics, when comparing the means of two independent groups of subjects using an unpaired Student t test, the effect size is expressed as the ratio of Δ

### Sample Size Estimation for Paired Student t Tests in Biostatistics

In biostatistics, when comparing paired measurements (such as changes between two time points for the same subject) using a paired Student t test, the

### Estimating Sample Size When Comparing Two Proportions in Biostatistics

The proportion of subjects having some attribute (such as responding to treatment) can be compared between two groups of subjects by creating a cross-tab from the data, where the two rows represent the

### Biostatistics For Dummies Cheat Sheet

To estimate sample size in biostatistics, you must state the effect size of importance, or the effect size worth knowing about. If the true effect size is less than the “important” size, you don’t care

### How Can Paralysis Be Cured?

Paralysis has multiple causes. The part of the brain that controls movement can be damaged, such as from a stroke. Injuries and diseases can interrupt the message transmitted from the brain to the muscles

As computers become more powerful, there is increasing speculation about whether they could equal or surpass human intelligence. One thread in this discussion is the idea of downloading our minds into

### Can Imaging Systems Read Our Minds?

Since functional magnetic resonance imaging (fMRI) machines became more common at the end of the 20th century, there have been more claims about the ability of this technology to extract the content of

### Are Cyborgs Possible?

Cyborgs (cybernetic organisms) already exist! Any one of the more than 100,000 people worldwide who has a cochlear implant to restore hearing is essentially a cyborg, a functional combination of organic

### Neurobiology For Dummies Cheat Sheet

Neurobiology has all kinds of real-world (and not so real-world) applications. From curing paralysis to the possibility of cyborgs, neurobiology has answers to many fascinating questions.

### What Is Consciousness and Where Is It Located?

People often ask where consciousness is in the brain, but that question is problematic. The question assumes that consciousness is some special entity embedded within the nervous system. This assumption

### Can Vision Be Restored for the Blind?

Most blindness is due to the death of photoreceptors in the retina, such as in retinitis pigmentosa and macular degeneration. Another leading cause of blindness is death of retinal ganglion cells from

### Is Depression “All in Your Mind”?

Every day, another genetic anomaly underlying a mental illness makes the headlines. Evidence of serotonin (a neurotransmitter) disorders has led to the widespread use of prescription medications such as

### 10 Careers for Neurobiology Students

If you’re a neurobiology student, or you’re thinking about pursuing a PhD in neurobiology, you may be wondering what people do with PhDs after graduation.

### The Building Blocks of Mathematical Formulas for Biostatistics

No matter how they're written, mathematical formulas are just concise "recipes" that tell you how to calculate something or how something is defined. You just have to know how to read the recipe. To start

### Powers, Roots, and Logarithms for Use in Biostatistics

These three mathematical operations — working with powers, roots, and logarithms — are all related to the idea of repeated multiplication. These basic functions are used to help build more complex formulas

### Factorials and Absolute Values

Most mathematical operators are written between the two numbers they operate on, or before the number if it operates on only one number (like the minus sign used as a unary operator). But factorials and