Flashcards in Chap 4 The Normal Distribution Deck (22):
When the ends, or "tails", of a distribution never intersect with the x-axis; they extend indefinitely.
The common term for a normal distribution. It is called a bell curve because of its bell like shape.
When a sample is not selected randomly, it may be a biased sample. A sample is biased when the members are selected in a way that systematically over represents some segment of the population and underrepresents other segments
When a sample is selected because it is convenient rather then random.
Statistics that describe the characteristics of a given sample or population. These statistics are only meant to describe the characteristics of those from whom data were collected.
Statistics generated from sample data that were used to make inferences about the characteristics of the population the sample is alleged to represent.
The shape of a distribution of scores in terms of its flatness or peakedness.
A term regarding the shape of a distribution. A leptokurtic distribution is one with a higher peak and thinner walls.
When a tail of a distribution of scores extends toward the lower end of the distribution.
A bell-shaped frequency distribution of scores that has the mean, median, and mode in the middle of the distribution and is symmetrical and asymptotic
A hypothesis that there is no effect
A term regarding the shape of a distribution. A platykurtic distribution is one with a lower peak and thicker tails
A group from which data is collected or a sample is selected. the population encompasses the entire group for which the data are alleged to apply.
When the tail of the distribution os scores extends towards the upper end of the distribution
The likelihood of an event occurring
A method of selecting a sample in which every member of the population has a equal chance of being selected.
A method of selecting a sample in which members are purposely selected to create a sample that represents the population on the same characteristic(s) of interest.
e.g. when a sample is selected to have the same percentages of various ethnic groups as the larger population.
An individual or group, selected from a population, from whom data are collected.
The degree to which a distribution of scores deviates from the normal in terms of asymmetrical extension of the tails.
When a distribution has the same shape on either side of the median
A distribution based on statistical probabilities rather than empirical data