Introduction to Biostatistics for Research Methods

Research Methods and Biostatistics

• The presentation is about research methods and biostatistics, specifically for undergraduate students.
• The presenter is Dr. Walhan AlShaer, director of the Pharmacological and Diagnostic Research Center at Al-Ahliyya Amman University (AAU).
• He is also a senior research scientist at the Cell Therapy Center at the University of Jordan.

Lecture: Introduction to Biostatistics

• The lecture introduces biostatistics, focusing on basic statistical concepts.

Basic Statistical Concepts

• Descriptive Statistics: Measures of Central Tendency and Variability
  • Descriptive statistics summarize and describe data, providing insights into central tendency and variability.
  • Key measures include:
    • Arithmetic Mean (Average): The sum of all values divided by the number of values, commonly used in various situations (e.g., average item).
    • Median: The middle value in a sorted dataset; robust to outliers and useful in skewed distributions.
    • Mode: The most frequently occurring value; useful in categorical data and identifying trends/preferences.
    • Geometric Mean: The nth root of the product of all values; helpful for exponentially related values or wide ranges (e.g., investments, growth).
    • Harmonic Mean: The reciprocal of the arithmetic mean of the reciprocals of the values; useful for rates or ratios (e.g., speed, production costs).
    • Range: The difference between the largest and smallest values in a dataset.
    • Variance: Measures how far each data point is from the mean.
    • Standard Deviation: The square root of the variance; measuring data spread around the mean.
  • Examples are provided for each concept to illustrate practical applications.

Measures of Central Tendency

• Arithmetic Mean (AM):
  • The sum of all values divided by the count.
  • The most common measure of central tendency.
  • Formula: Σx/N
• Geometric Mean (GM):
  • The nth root of the product of all values
  • Used for exponentially related values
  • Formula: ⁿ√(x₁ * x₂ * ... * xₙ)
• Harmonic Mean (HM):
  • The reciprocal of the arithmetic mean of the reciprocals of the values.
  • For rates or ratios such as speed or density.
  • Formula: n / (1/x₁ + 1/x₂ + ... + 1/xₙ)
• Median:
  • The middle value when data is arranged in ascending order.
  • Not affected by outliers.
  • Useful in skewed distributions.
• Mode:
  • The most frequent value in a dataset.
  • Useful in categorical data and identifying preferences.

Measures of Variability (Dispersion)

• These measures describe how spread out the data is.
• Important concepts are Range, Variance and Standard Deviation.