| Identify the underlined phrase:The research team at the hospital selected 16 employees at random, and tested their BUN levels, and found an average of 16 mg/dL with a standard deviation of 6.5 mg/dL. They used this data to construct a range of normal values for the whole healthy population. | View Page |
| Introduction to Statistics Statistics is the branch of mathematics that deals with the organization, analysis, and interpretation of information. It is often said that statistics is the opposite of probability. A probability question would be, "If I have a fair coin and toss it ten times, how often will I get seven or more heads?" A statistics question would be "I toss a coin ten times and get seven heads. Given this information, how likely is it that this coin is fair?"Many people are uncomfortable with statistics. Statistics is one of the more confusing mathematical subjects, and deals with many subtle concepts. Often the interpretation of a result is more difficult than calculating the result in the first place. This course will attempt to make clear both the calculations and the interpretation of those results. | View Page |
| Why Statistics? Many people involved in the clinical laboratory sciences need to be familiar with basic statistics for a variety of reasons. These reasons include: performing quality control, and interpreting of results of instrument testing determining suitability of different methods or instruments for the same task understanding how acceptable laboratory procedures and methods are established determining ranges for clinical tests of normal, healthy individuals understanding clinical trials and new methods presented in journals and articles performing those trials and research projects yourself | View Page |
| Descriptive Statistics Descriptive statistics deals with the enumeration, organization, and graphic representation of data. The other main branch, inferential statistics, deals with making conclusions about a population based on information in a small sample.This course will deal primarily with descriptive statistics. | View Page |
| What common tasks in the clinical laboratory require knowledge of basic statistics? | View Page |
| Independent and Dependent Variables In statistics, a variable is any quantity that is a part of a data point. Variables can either be dependent or independent. An independent variable is a quantity that is directly controlled by the observer or experimenter. The dependent variable, as its name suggests, depends on the independent variable. The dependent variable is often the quantity you want to measure, and it the result of the experiment or test.For example, you may want to determine the relationship between hemoglobin concentration and age. You select people of various ages, and then test their hemoglobin concentrations. Age is the independent variable, and is controlled by the experimenter (you can select which ages are in the experiment). The dependent variable is the resulting hemoglobin concentration.In some cases, these criteria may not be useful in determining which variable should be the independent variable, such as determining the correlation between the readings given by two different instruments for the same samples. In that case, there might be other criteria for selecting the independent variable. | View Page |
| Statistics and Parameters Raw information collected from an experiment or test is called data. However, it would be very impractical and difficult to list all of one's data in a report, and the reader would have a hard time making sense of it anyway. Therefore, researchers commonly report just a few numbers, called statistics, which attempt to capture all of the essential information about the whole data set.Common statistics include the mean, the standard deviation, the median, the maximum, and the minimum. The statistics you use will depend on the kind of data being studiedA parameter is a property of the population, and since you cannot measure all of the members of a population, you cannot measure a parameter directly. You can however make inferences about a parameter, based on your statistics. | View Page |
| Read the following passage, and identify the underlined words: The researchers tested 50 students chosen at random who had taken calculus in high school, and determined their math SAT scores. The average score was 600. According to the College Board, the average math SAT score for all students was 480. The researchers conclude that students who take calculus are better prepared for the math SAT test. | View Page |
| Read the following passage, and identify the underlined words: The researchers tested 50 students chosen at random who had taken calculus in high school, and determined their math SAT scores. The average score was 600. According to the College Board, the average math SAT score for all students was 480. The researchers conclude that students who take calculus are better prepared for the math SAT test. | View Page |
| Read the following passage, and identify the underlined words: The researchers tested 50 students chosen at random who had taken calculus in high school, and determined their math SAT scores. The average score was 600. According to the College Board, the overall average math SAT score was 480. The researchers conclude that students who take calculus are better prepared for the math SAT test. | View Page |
| Mean The mean, also called the arithmetic mean or the average, is simply the sum of all the data points divided by the number of points. It is denoted with . The formula for the mean is: For example, here are the number of hours that some students worked on a project: # hours worked 4 6 2 8 5 The average time spent working was: The average is the most common way of calculating central tendency. Some of its characteristics are: easy to calculate only one exists for any data set affected by all observations, and therefore strongly affected by outliers used in many statistics calculations | View Page |
| Standard Deviation (continued) All of these distributions have the same mean (62%) but you can see that they differ greatly. The difference lies in their spread. Set A is the most spread out, while C is the most clustered. One way of quantifying this spread is with the standard deviation, which is denoted with s.To calculate the standard deviation, first find for each point, square the results, add them, divide by n-1, and finally take the square root. The formula is: As you can see, the farther points are from the mean, the larger the standard deviation will be. The standard deviation is a statistic calculated from a set of data. However, the term can also refer to the parameter that describes the spread of the data in the whole population. We sometimes use "population standard deviation" and the Greek letter s to distinguish this parameter from the "sample standard deviation" statistic, which is denoted with s. | View Page |