BIOSTATISTICS

Question 1

The raw material of statistics is data. For our purposes we may define data as
numbers. The two kinds of number that we use in statistics are numbers that result from the
taking—in the usual sense of the term—of a measurement, and those that result from the
process of counting.
For example, when a nurse weighs a patient or takes a patient’s temperature, a
measurement, consisting of a number such as 150 pounds or 100 degrees Fahrenheit, is
obtained. Quite different type of number is obtained when a hospital administrator counts the number of patients—perhaps 20—discharged from the hospital on a given day. Each of
the three numbers is a datum, and the three taken together are data.

Answer 1

DATA

Question 2

A field of study concerned with (1) the collection, organization, summarization,
and analysis of data; and (2) the drawing of inferences about a body of data when only a part of the data is observed. The person who performs these statistical activities must be prepared to interpret and communicate the results to someone else as the situation demands. Simply put, data are numbers, numbers contain information, and the purpose of statistics is to investigate and evaluate the nature and meaning of this information.

Answer 2

STATISTICS

Question 3

The performance of statistical activities is motivated by the need
to answer a question. For example, clinicians may want answers to questions regarding the
relative merits of competing treatment procedures, etc.

Answer 3

SOURCES OF DATA

Question 4

The maintenance of a history of one’s activities, as financial dealings, by entering data in ledgers or journals, putting documents in files, etc. For example, Hospital medical records contain immense amounts of information on patients.

Answer 4

ROUTINELY KEPT RECORDS

Question 5

If the data needed to answer a question are not available from routinely kept records, the logical source may be a survey. For example, the
Administrator of a clinic wishes to obtain information regarding the mode of transportation used by patients to visit the clinic.

Answer 5

SURVEYS

Question 6

Frequently the data needed to answer a question are available only as the result of an experiment. A nurse may wish to know which of several strategies is best in maximizing patient compliance. The nurse might conduct an experiment in which different strategies of motivating compliance are tried with different patients. Subsequent evaluation of the responses to the different strategies might enable the nurse to decide which is most effective.

Answer 6

EXPERIMENT

Question 7

The data needed to answer a question may already exist in the form of published reports, commercially available data banks, or the research literature.

Answer 7

EXTERNAL SOURCES

Question 8

When the data analyzed are derived from the biological sciences and medicine, we use the term biostatistics to distinguish this particular application of statisticaltools and concepts.

Answer 8

BIOSTATISCTICS

Question 9

If, as we observe a characteristic, we find that it takes on different values in different persons, places, or things, we label the characteristic a variable. We do this for the simple reason that the characteristic is not the same when observed in different possessors of it.

Answer 9

VARIABLE

Question 10

One that can be measure in the usual sense. Measurement made on _______ convey information regarding amount. For example, we can obtain measurements on the heights of adult males, the weights of preschool children, and the ages of patients seen in a dental clinic.

Answer 10

QUANTITATIVE VARIABLES

Question 11

Measuring consists of categorizing. Measurements made on _______ convey information regarding attribute. For example, when an ill person is given a medical diagnosis, a person is designated as belonging to an ethnic group, or a person, place, or object is said to possess or not to possess some characteristics of
interest

Answer 11

QUALITATIVE VARIABLES

Question 12

Whenever we determine the height, weight, or age of an individual, the result is frequently referred to as a value of the respective variable. When the values obtained arise as a result of chance factors, so that they cannot be exactly predicted in advance. For example, an adult height. When a child is born, we cannot predict exactly his or her height at maturity. Attained adult height is the result of numerous genetic and environmental factors.

Answer 12

RANDOM VARIABLES

Question 13

Is characterized by gaps or
interruptions in the values that it can assume. These gaps or interruptions indicate the
absence of values between particular values that the variable can assume. Some examples
illustrate the point. The number of daily admissions to a general hospital is a ______ since the number of admission each day must be represented by a whole number, such as 0, 1, 2, or 3. The number of decayed tooth of a child in an elementary school is another example of a _________ since it cannot be represented as
1.5, 3.3333, and so on.

Answer 13

DISCRETE RANDOM VARIABLE

Question 14

Does not possess the gaps or
interruptions characteristic of a discrete random variable. It can assume any value within a
specified interval of values assumed by the variable. For example, the various
measurements that can be made on individuals such as height, weight, and the skull
circumference. No matter how close together the observed height of two people, we can,
theoretically, find another person whose height falls somewhere in between.

Answer 14

CONTINUOUS RANDOM VARIABLE

Question 15

A collection of entities may consist of people, animals, machines, places, or cells. For our purposes, we define a population of entities as the largest collection of entities for which we have an interest at a particular time. If we take a
measurement of some variable on each of the entities in a population, we generate a
population of values of that variable. We may, therefore, define a population of values as the
largest collection of values of a random variable for which we have an interest at a particular time. For example, we are interested in the weights of all the children enrolled in a certain county elementary school system, our population consists of all these weights. Populations are determined or defined by our sphere of interest. It may be finite or infinite. If a population of values consists of a fixed number of these values, the population is said to be finite. It is consists of an endless succession of values, the population is an infinite one.

Answer 15

POPULATION

Question 16

Is defined as a part of a population. Suppose our population consists of the weights of all the elementary school children enrolled in a certain county school system. If we collect for analysis the weights of only a fraction of these children, we have only a part of our population of weights, that is.

Answer 16

SAMPLE

Question 17

This may be defined as the assignment of numbers to objects or events according to a set of rules. The various measurement scales result from the fact that the measurement may be carried out under different sets of rules.

Answer 17

MEASUREMENT

Question 18

it consists of “naming” observations or classifying them into various mutually exclusive and collectively exhaustive categories. The practice of using numbers to distinguish among the various medical diagnoses constitutes measurement on a _______. For example, dichotomies as male-female, well-sick, under 65 years of age-65 and over, child-adult, married-not married.

Answer 18

THE NOMINAL SCALE

Question 19

Whenever observations are not only different from category to category but can be ranked according to some criterion, they are said to be measured on an ______. For example, convalescing patients may be characterized as unimproved, improved, and much improved. Individuals may be classified according to socioeconomic status as low, medium, or high. The intelligence of children may be above average, average, or below average.

Answer 19

ORDINAL SCALE

Question 20

This is more sophisticated scale than the nominal or ordinal in that with this scale not only it it possible to order measurements, but also the distance between any two measurements is known. For example, the difference between a measurement of 20 and a measurement of 30 is equal to the difference between measurements of 30 and 40.

Answer 20

THE INTERVAL SCALE

Question 21

The highest level of measurement. This scale is characterized by the fact that equality of ratio as well as equality of intervals may be determined. Fundamental to the ratio is a true zero. For example, the measurement of such familiar traits as height, weight, and length.

Answer 21

THE RATIO SCALE

Question 22

Is the procedure by which we reach a conclusion about a population on the basis of the information contained in a sample that has been drawn from that population. There are many kinds of samples that may be drawn from a population. In order to make valid inference about a population, we need a scientific samples that may be drawn from a population.

Answer 22

STATISTICAL INFERENCE

Question 23

If a sample of size n is drawn from a population of size N in such a way that every possible sample of size n has the same chance of being selected, the sample is called a _______.

Answer 23

SIMPLE RANDOM SAMPLING

Question 24

A sampling method that is widely used in healthcare research is the _______. Medical records, which contain raw data used in healthcare research are generally stored in a file system or on a computer and hence are easy to select in a systematic way. Using ______ methodology, a researcher calculates the total number of records needed for the study or experiment at hand.

Answer 24

SYSTEMATIC SAMPLING

Question 25

A common situation that may be encountered in a population under study is one in which the sample units occur together in a grouped fashion. On occasion, when the sample units are not inherently grouped, it may be possible and desirable to group them for sampling purposes. In other words, it may be desirable to partition a population of interest into groups, or strata, in which the sample units within a particular stratum are more similar to each other than they are to sample units that compose the other strata. After the population is stratified, it is customary to take a random sample independently from each stratum.

Answer 25

STRATIFIED RANDOM SAMPLING

Question 26

Is a process by which scientific information is collected, analyzed, and reported in order to produce unbiased and replicable results in an effort to provide an accurate representation of observable phenomena.

Answer 26

SCIENTIFIC METHOD

Question 27

Is made of a phenomenon or a group phenomenon. This observation leads to the formulation of questions or uncertainties that can be answered in a scientifically rigorous way. For example, it is readily observable that regular exercise reduces body weight in many people. It is also readily observable that changing diet may have a similar effect. In this case there are two observable phenomena, regular exercise and diet change, that have the same endpoint.

Answer 27

MAKING AN OBSERVATION

Question 28

Is formulated to explain the observation and to make quantitative predictions of new observations. For example, a research hypothesis from the weight-loss example would be a statement such as, “Exercise appears to reduce body weight.” A statistical hypothesis may be stated using quantitative terminology as follows: “The average (mean) loss of body weight of people who do exercise is greater than the average (mean) loss of body weight of people who do not exercise.” in this statement a quantitative measure, the “average” or “mean” value, is hypothesized to be greater in the sample of patients who exercise.

Answer 28

FORMULATING A HYPOTHESIS

Question 29

The third step in the scientific method will yield the data to validly test an appropriate statistical hypothesis. This step of the scientific method, like that of data analysis, requires the expertise of a statistician. Improperly designed experiments are the leading cause of invalid results and unjustified conclusions. Those who properly design research experiments make every effort to ensure that the measurement of the phenomenon on interest is both accurate and precise. Accuracy refers to the correctness of a measurement. Precision, on the other hand, refers to the consistency of a measurement. It should be noted that in the social sciences, the term validity is sometimes used to mean accuracy and that reliability is sometimes used to mean precision. For example, in the context of of the weight-loss, the scale used to measure the weight of study participants would be accurate if the measurement is validated using a scale that is properly calibrated. If, however, the scale is off by +3 pounds, then each participants weight would be 3 pounds heavy; the measurements would be precise in that each would be wrong by +3 pounds, but the measurements would not be accurate. Measurements that are inaccurate or imprecise may invalidate research findings. The design of an experiment depends on the type of data need to be collected to test a specific hypothesis. For much scientific research, however, the standard for data collection is experimentation.

Answer 29

DESIGNING AN EXPERIMENT

Question 30

In the execution of a research study or experiment, one would hope to have collected the data necessary to draw conclusions, with some degree of confidence, about the hypotheses that were posed as part of the design. Whatever the conclusions of the scientific process, however, results are rarely considered to be conclusive.

Answer 30

CONCLUSION

Question 31

Is a systematic process of gathering observations or measurements. Whether you are performing research for business, governmental or academic purposes, data collectionallows you to gain first-hand knowledge and original insights into yourresearch problem.

Answer 31

DATA COLLECTION

Question 32

Is the practice of categorizing and classifying data to make it more usable. Similar to a file folder, where we keep important documents, you’ll need to arrange your data in the most logical and orderly fashion, so you — and anyone else who accesses it — can easily find what they’re looking for.

Answer 32

DATA ORGANIZATION

Question 33

Refers to an exhibition or putting up data in an attractive and useful manner such that it can be easily interpreted. The three main forms of presentation of data are: Textual presentation. Data tables. Diagrammatic presentation.

Answer 33

DATA REPRESENTATION

Question 34

Is a technique that involves systematically selecting, watching and recording behaviors of people or other phenomena and aspects of the setting in which they occur, for the purpose of getting (gaining) specified information. It includes all methods from simple visual observations to the use of high level machines and measurements, sophisticated equipment or facilities, such as radiographic, biochemical, X-ray machines, microscope, clinical examinations, and microbiological examinations.

Answer 34

OBSERVATION

Question 35

A good interview can stimulate and maintain the respondent’s interest and can create a rapport (understanding, concord) and atmosphere conducive to the answering of questions. If anxiety aroused, the interviewer can allay it. If a question is not understood an interviewer can repeat it and if necessary provide an explanation or alternative wording.

Answer 35

FACE-TO-FACE AND TELEPHONE INTERVIEWS

Question 36

Under this method, the researcher prepares a questionnaire containing a number of questions pertaining the field of inquiry. The questionnaires are sent by post to the informants together with a polite covering letter explaining the detail, the aims and objectives of collecting the information, and requesting the respondents to cooperate by furnishing the correct replies and returning the questionnaire duly filled in.

Answer 36

MAILED QUESTIONNAIRE METHOD

Question 37

Clinical and other personal records, death certificates, published mortality statistics, census publications. During the use of data from documents, though they are less time consuming and relatively have low cost, care should be taken on the quality and completeness of the data.

Answer 37

USE OF DOCUMENTARY SOURCES

Question 38

These are data which are collected by the investigator/researcher himself for the purpose of a specific inquiry or study. Such data are original in character and are mostly generated by surveys conducted by individuals or research institutions.

Answer 38

PRIMARY DATA

Question 39

When a researcher or investigator uses data, which have already been collected by others, such data are called _______. Such data are primary data for the agency that collected them, and become secondary for someone else who uses these data for his own purposes. These secondary data can be obtained from journals, reports government publications of professionals and research organizations. Secondary data are less expensive to collect both in money and time. These data can also be better utilized and sometimes the quality of such data may be better because these might have been collected by persons who were specially trained for that purpose.

Answer 39

SECONDARY DATA

Question 40

This permits free responses that should be recorded in the respondent’s own words. The respondent’s own words. The respondent is not given any possible answers to choose from. Such questions are useful to obtain information on:
-Facts with which the researcher is not very familiar,
-Opinions, attitudes, and suggestions of information
-Sensitive issues.

Example:
Can you describe what it means to eat healthy foods? What are healthy foods?

Answer 40

OPEN-ENDED QUESTIONS

Question 41

Offer a list of possible options or answers from which the respondents must choose. When designing closed questions one should try to:

-Offer a list of options that are exhaustive and mutually exclusive
-Keep the number of options as few as possible.

Closed questions are useful if the range of possible responses is known.

For example:
“What is your marital status?”
1.Single
2.Married
3.Widowed/separated

Answer 41

CLOSED QUESTIONS

Question 42

The question that we design should be one that give an obviously valid and relevant measurement for the variable.

Answer 42

MUST HAVE FACE VALIDITY

Question 43

The way in which the questions are worded can ‘make or break’ a questionnaire. They must be phrased in language that it is believed the respondent will understand in the same way.

Answer 43

MUST BE CLEAR AND UNAMBIGUOUS

Question 44

Whenever possible, it is wise to avoid questions that may offend the respondent, for example those that deal with intimate matters, those which may seem to expose the respondent’s ignorance, and those requiring him to give a socially unacceptable answer.

Answer 44

MUST NOT BE OFFENSIVE

Question 45

They should not be phrased in a way that suggests a specific answer, and should not be loaded.

Answer 45

THE QUESTIONS SHOULD BE FAIR

Question 46

Is the practice of categorizing and classifying data to make it more usable. Similar to a file folder, where we keep important documents, you’ll need to arrange your data in the most logical and orderly fashion, so you — and anyone else who accesses it — can easily find what they’re looking for.

Answer 46

DATA ORGANIZATION

Question 47

The data collected in a survey or any method of data collection is called ________. In most cases, useful information is not immediately evident from the mass of unsorted data. Collected data need to be organized in such a way as to condense the information they contain in a way that will show patterns of variation clearly. Precise methods of analysis can be decided up only when the characteristics of the data are understood. For the primary objective of this different techniques of data organization and presentation like ordered array, table and diagrams are used.

Answer 47

RAW DATA

Question 48

It is a listing of the values of a collecting (either population or sample) in order of magnitude from the smallest value to largest value. If the number of measurement to be ordered is of appreciable size, the use of a computer to prepare the ordered array is highly desirable. Enables one to determine quickly the value of the smallest measurement, the value of the largest measurement, and other facts about the arrayed data that might be needed in a hurry.

Answer 48

AN ORDERED ARRAY