Chap 4 The Normal Distribution

Question 1

Asymptotic

Answer 1

When the ends, or “tails”, of a distribution never intersect with the x-axis; they extend indefinitely.

Question 2

Bell Curve

Answer 2

The common term for a normal distribution. It is called a bell curve because of its bell like shape.

Question 3

Biased

Answer 3

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

Question 4

Convenience Sampling

Answer 4

When a sample is selected because it is convenient rather then random.

Question 5

Descriptive Statistics

Answer 5

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.

Question 6

Inferential Statistics

Answer 6

Statistics generated from sample data that were used to make inferences about the characteristics of the population the sample is alleged to represent.

Question 7

Kurtosis

Answer 7

The shape of a distribution of scores in terms of its flatness or peakedness.

Question 8

Leptokurtic

Answer 8

A term regarding the shape of a distribution. A leptokurtic distribution is one with a higher peak and thinner walls.

Question 9

Negatively Skewed

Answer 9

When a tail of a distribution of scores extends toward the lower end of the distribution.

Question 10

Normal Distribution

Answer 10

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

Question 11

Null hypothesis

Answer 11

A hypothesis that there is no effect

Question 12

Platykurtic

Answer 12

A term regarding the shape of a distribution. A platykurtic distribution is one with a lower peak and thicker tails

Question 13

Population

Answer 13

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.

Question 14

Positively Skewed

Answer 14

When the tail of the distribution os scores extends towards the upper end of the distribution

Question 15

Probability

Answer 15

The likelihood of an event occurring

Question 16

Random Sampling

Answer 16

A method of selecting a sample in which every member of the population has a equal chance of being selected.

Question 17

Representative Sampling

Answer 17

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.

Question 18

Sample

Answer 18

An individual or group, selected from a population, from whom data are collected.

Question 19

Skew

Answer 19

The degree to which a distribution of scores deviates from the normal in terms of asymmetrical extension of the tails.

Question 20

Symmetrical

Answer 20

When a distribution has the same shape on either side of the median

Question 21

Theoretical Distribtution

Answer 21

A distribution based on statistical probabilities rather than empirical data

Question 22

Unimodal

Answer 22

A distribution that has a single mode.