Module 7/8: Biostatistics - Nathe Chapter 17

Comprehensive practice flashcards covering biostatistics definitions, variable and scale categorizations, measures of central tendency and dispersion, and data visualization based on Nathe Chapter 17.

What is the definition of biostatistics?

The use of data analysis and interpretations in health care research.

What are several ways biostatistics are used in dental hygiene (DH)?

To demonstrate response to dental hygiene therapy, test products and treatment regimens, determine needs of target populations, evaluate oral health treatment, prevent dental disease, and develop education programs.

Name five factors that can cause inappropriate statistical analysis leading to misinterpretation of study results.

Insufficient number of subjects, too short of a duration, incorrect measurement instruments, incorrect procedures, and incorrect statistical tests.

Distinguish between the terms 'data' and 'datum'.

Data is plural (information collected by a researcher/a mass of data items), while datum is singular (each piece of information).

What is the difference between quantitative and qualitative data?

Quantitative data are numerical representations expressed as counts, percentages, and means; Qualitative data reflects the quality or nature of variables that cannot be measured numerically.

What is a continuous variable?

A variable made up of distinct and separate units expressed by a large or infinite number of measures along a continuum; it can be expressed as fractions (e.g., height, weight, time).

What is a discrete variable and what is a dental-specific example?

A variable made up of distinct units counted only in whole numbers; a dental index like DMFT is discrete because you cannot count a fraction of a tooth.

What is a dichotomous variable?

A variable that places data into only two groups, such as male/female, pass/fail, or yes/no.

Define the nominal scale of measurement.

A scale that organizes data into mutually exclusive categories with no rank order, value, or numeric relationship (e.g., ethnic group membership).

How is the ordinal scale of measurement characterized?

It organizes data into mutually exclusive categories that are rank ordered, but the difference between ranks is not equal in value (e.g., calc codes $1$, $2$, $3$, and $4$).

What defines an interval scale of measurement?

It has characteristics of the ordinal scale plus equal distance between any two adjacent units, but it lacks a meaningful zero point (e.g., Fahrenheit scale).

What is the primary characteristic of a ratio scale of measurement?

It includes all characteristics of preceding scales and has an absolute zero point where all arithmetic procedures can be applied (e.g., blood pressure, height, weight).

What is the difference between descriptive and inferential statistics?

Descriptive statistics summarize, organize, and describe quantitative data (tables/graphs); Inferential statistics make generalizations about a population based on a sample.

Name the three measures of central tendency.

Mean (arithmetic average), Median (midpoint of the data), and Mode (value that occurs most often).

What are measures of dispersion (measures of variability)?

Methods that communicate how much variation is present in a group of data, including range, variance, and standard deviation.

How is the range calculated, and what is its main limitation?

It is determined by subtracting the lowest score from the highest score; it is the simplest but least helpful measurement.

Describe the characteristics of a normal distribution (Gaussian curve).

It is a bell-shaped curve where the majority of scores fall in the middle, and the mean, median, and mode are equal in value.

According to the Empirical Rule, what percentage of data falls within $1$, $2$, and $3$ standard deviations of the mean in a normal distribution?

Approximately $68\%$ within $1$ SD, $95\%$ within $2$ SD, and $99.7\%$ within $3$ SD.

What is the Central Limit Theorem's significance regarding sample size?

It suggests less sampling error occurs with larger samples, specifically a sample size of $30$ or more.

What is the difference between positively and negatively skewed distributions?

Positively skewed (right-skewed) has the tail in a positive direction and the mean is larger than the median; Negatively skewed (left-skewed) has the tail in a negative direction and the mean is smaller than the median.

What is the visual difference and functional use of a bar graph compared to a histogram?

A bar graph has spaces between bars and presents categorical data; a histogram has bars side-by-side (touching) and is used for interval, ratio, or continuous ordinal data.

What are the recommendations for using ungrouped versus grouped frequency distributions?

Ungrouped is for small samples with less than $30$ observations; Grouped is recommended for larger samples or if the range between high and low values is more than $15$.

What does a scattergram show?

It shows the relationship between two variables and how the level of one variable varies as the level of the other changes.