Research methods

• Levels of measurement in research involve different types of data: nominal, ordinal, interval, and ratio
• Nominal data categorizes information without providing precision, like gender categories or pass/fail outcomes
• Ordinal data orders information but doesn't specify the intervals between values, like rating scales or rankings
• Ordinal data doesn't show the exact distance between values, just the order they come in
• Interval and ratio data provide more precise measurements with equal intervals between values, like standardized tests or time measurements
• Public scales are an example of interval and ratio data, where each unit has the same value and precise measurements can be made
• When measuring time, each minute is exactly the same as the other minute, making it interval or ratio data
• Distance measurements like meters, centimeters, millimeters, and temperature readings from thermometers are also examples of interval or ratio data
• If data is measured by a device or machine like a clock, thermometer, or tape measure, it's considered interval or ratio data
• Scores on standardized tests, where each question gets you the same marks, are examples of ratio data
• IQ scores from IQ tests are standardized, where each IQ score point is one unit, making it ratio data
• Interval data has zero as part of the measurement, while zero in ratio data means nothing
• Temperature is an example of interval data, but it's rarely used in psychology
• Nominal data has no units of measurement, just categories like yes or no
• Ordinal data means the units of measurement are not in an equal scale, like rating scales
• Ratio data is the most precise, with each unit of measurement being equal, while interval data is less precise because zero can muddy the data
• Data from a psychologist's study on reading confidence in primary school children, where teachers rated confidence levels as low, medium, or high, is an example of ordinal data
• A study on the number of times a book was borrowed from a college library is an example of nominal data
• A study on the impact of violent computer games on school children's aggression, where incidents of aggression were recorded as either present or not, is an example of nominal data
• A research study comparing police officers and students on their ability to identify true or false statements is an example of ordinal data when looking at the scores out of ten
• The researcher must be aware that the data collected may not always reflect reality.
• It is important to acknowledge any limitations or weaknesses in the research design and methodology.
• Researchers need to consider how their own beliefs, values, and attitudes can influence the research process.
• Researchers need to consider how they will collect information about participants' thoughts, feelings, and experiences.
• There are two main ways to gather this type of data - self-reporting (questionnaires) and observation.
• Researchers need to consider how they will collect valid and reliable data.
• Muscle contraction

  Occurs in antagonistic pairs, as one muscle contracts, the other relaxes causing movement of the skeleton. Can be automatic as part of a reflex response or controlled by conscious thought
• Myofibril

  • Made up of fused cells sharing nuclei and cytoplasm, with a high number of mitochondria for ATP production essential for muscle contraction
• Sarcomere

  • Thread-like structures bundled together within myofibrils, composed of myosin and actin proteins creating the sliding filament theory
• Muscle fibers

  • Composed of millions of myofibrils fused together, collectively responsible for the movement of the skeleton
• Myosin and Actin proteins

  • Key proteins in muscle fibers, creating the sarcomere with myosin being thicker and actin being thinner, forming thin and thick filaments
• Sliding filament theory


  When an action potential reaches a muscle, calcium ions are released from the sarcoplasmic reticulum, binding to tropomyosin which uncovers binding sites on actin for myosin attachment, leading to muscle contraction
• Release of calcium ions

  Allows binding to tropomyosin, exposing binding sites on actin for myosin attachment
• Muscle contraction

  Requires the presence of calcium ions binding to tropomyosin to expose actin binding sites for myosin attachment
• Muscle contraction process

  1. Calcium ions bind to troponin, moving tropomyosin and exposing binding sites

  2. Myosin heads attach to exposed binding sites while ADP is attached to the myosin head

  3. Myosin head creates a cross bridge with actin, creating tension and sliding the actin filament along the myosin

  4. ADP and Pi are released during movement

  5. New ATP molecule binds to myosin head, causing a change in shape and detachment from actin

  6. ATPase enzyme hydrolyzes ATP attached to myosin head, releasing energy for myosin head to return to original position

  7. Process repeats until muscle contraction stops due to lack of ATP or inability to move axon closer together
• Muscle contraction is stimulated by the nervous system as long as calcium ions are released and ATP is present
• ATP is crucial for muscle contractions due to its role in providing energy for the process
• High concentrations of ATP are required for full muscle contraction, leading to the abundance of mitochondria in myofibrils
• Aerobic respiration may be insufficient to meet ATP demands during intense activities like sprinting, leading to anaerobic respiration
• Phosphocreatine in muscles helps regenerate ATP from ADP rapidly during high-intensity activities