bell curve

Examples of bell curve in the following topics:

• IQ Tests

  • Scores on IQ tests tend to form a bell curve with a normal distribution.
  • It is a statistical law that under a normal curve, 68% of scores will lie between -1 and +1 standard deviation, 95% of scores will lie between -2 and +2 standard deviations, and >99% percent of scores will fall between -3 and +3 standard deviations.
  • In a normally distributed bell curve, half the scores are above the mean and half are below.
  • IQ test scores tend to form a bell curve, with approximately 95% of the population scoring between two standard deviations of the mean score of 100.

• History of Intelligence Testing

  • The Wechsler scales were the first intelligence scales to base scores on a standardized bell curve (a type of graph in which there are an equal number of scores on either side of the average, where most scores are around the average and very few scores are far away from the average).
  • Modern IQ tests now measure a very specific mathematical score based on a bell curve, with a majority of people scoring the average and correspondingly smaller amounts of people at points higher or lower than the average.
  • The bell shaped curve for IQ scores has an average value of 100.

• Descriptive and Correlational Statistics

  • Tools used for descriptive statistics include quantitative measures such as the mean, median, and mode, as well as a distribution curve.
  • The normal distribution curve exists when the mean and median are close together.
  • Also known as the bell curve.
  • When the mean, median, and mode are unequal, the normal curve can become skewed in either a negative or positive direction depending on their values in relation to each other.

• Basic Inferential Statistics

  • The normal, or Gaussian, distribution of values (also known as the bell curve).

• Basic Principles of Classical Conditioning

  • The conditioned stimulus was the ringing of the bell.
  • During conditioning, every time the animal was given food, the bell was rung.
  • After some time, the dog learned to associate the ringing of the bell with food and to respond by salivating.
  • After the conditioning period was finished, the dog would respond by salivating when the bell was rung, even when the unconditioned stimulus (the food) was absent.
  • The conditioned response, therefore, was the salivation of the dogs in response to the conditioned stimulus (the ringing of the bell) .

• Basic Descriptive Statistics

  • This histogram displays normally distributed data (it is shaped like a symmetrical bell, meaning the median is roughly equal to the mean).
  • When the mean, median, and mode are unequal, the normal curve can become skewed in either a negative or positive direction depending on their values in relation to each other.

• Basic Principles of Classical Conditioning: Pavlov

  • The conditioned stimulus was the ringing of the bell, which previously had no association with food.
  • The conditioned response, therefore, was the salivation of the dogs in response to the ringing of the bell, even when no food was present.
  • Over time, these synapses are strengthened so that it only takes the sound of a buzzer (or a bell) to activate the pathway leading to salivation.
  • Before conditioning, an unconditioned stimulus (food) produces an unconditioned response (salivation), and a neutral stimulus (bell) does not have an effect.
  • During conditioning, the unconditioned stimulus (food) is presented repeatedly just after the presentation of the neutral stimulus (bell).

• Defining Learning

  • Ivan Pavlov conducted a famous study involving dogs in which he trained (or conditioned) the dogs to associate the sound of a bell with the presence of a piece of meat.
  • The conditioning is achieved when the sound of the bell on its own makes the dog salivate in anticipation for the meat.

• Behavioral Psychology

  • In his famous 1890s experiment, he trained his dogs to salivate on command by associating the ringing of a bell with the delivery of food.

• Considerations for Eyewitness Testimony

  • The "forgetting curve" of eyewitness memory shows that memory begins to drop off sharply within 20 minutes following initial encoding, and begins to level off around the second day at a dramatically reduced level of accuracy.