Unit 2 Test

Question 1

Raw Score

Answer 1

unchanged scores that are the direct result of measurement

Question 2

Z-Score

Answer 2

specifies the precise location of each X value within a distribution

Question 3

Deviation Score

Answer 3

measures the distance in points between X and μ and indicates whether X is located above or below the mean

Question 4

Z-Score Transformation

Answer 4

if every X value is transformed into a z-score then the distribution of z-scores will have the following properties: Normal Shape, mean of 0, standard deviation of 1

Question 5

Standardized Distribution

Answer 5

composed of scores that have been transformed to create predetermined values for μ and σ

Question 6

Standardized Score

Answer 6

scores that have been standardized

Question 7

Probability

Answer 7

fraction or proportion of all the possible outcomes

Question 8

Random Sample

Answer 8

requires that each individual in the population has an equal chance of being selected

Question 9

Independent Random Sample

Answer 9

probability of selecting any particular individual is independent of those individuals who have already been selected for the sample

Question 10

Sampling with Replacement

Answer 10

Sampling with Replacement to keep the probabilities from changing form one selection to the next, it is necessary to return each individual to the population before you make the next selection

Question 11

Unit Normal Table

Answer 11

complete listing of z-scores and proportions

Question 12

Percentile Rank

Answer 12

the percentage of the individuals in the distribution who have scores that are less than or equal to the specific score

Question 13

Percentile

Answer 13

when a score is referred to by it’s percentile rank

Question 14

sampling error

Answer 14

the natural discrepancy, or amount of error, between a sample statistic and its corresponding population parameter

Question 15

distribution of sample means

Answer 15

collection of sample means for all of the possible random samples of a particular size (n) that can be obtained from a population

Question 16

Sampling Distribution

Answer 16

distribution of statistics obtained by selecting all of the possible samples of a specific size from a population

Question 17

Central Limit Theorem

Answer 17

for any population with a mean μ and standard deviation σ, the distribution of sample means for sample size n will have a mean of μ and a standard deviation of σ/ √n and will approach a normal distribution as n approaches infinity

Question 18

Expected Value of M

Answer 18

the mean of the distribution of sample means is equal to the mean of the population of scores, μ

Question 19

Standard Error of M

Answer 19

standard deviation for the distribution of sample means. provides a measure of how much distance is expected on average between a sample mean (M) and a population mean (μ)

Question 20

Law of large numbers

Answer 20

the larger the sample size (n), the more probable it is that the sample mean is close to the population mean

Question 21

Hypothesis Test

Answer 21

statistical method that uses sample data to evaluate a hypothesis about a population

Question 22

Null Hypothesis

Answer 22

in the general population there is no change, no difference, or no relationship. Independent variable has no effect on the dependent variable for the population

Question 23

alternative hypothesis

Answer 23

there is a change, difference, or relationship for the general population. independent variable has an effect of the dependent variable

Question 24

level of significance

Answer 24

is a probability value that is used to define the concept of “very unlikely” in a hypothesis test

Question 25

critical region

Answer 25

extreme sample values that are very unlikely to be obtained if the null hypothesis is true.

Question 26

Type I error

Answer 26

(say treatment has an effect when there is no effect)

Question 27

Type II Error

Answer 27

say treatment has no effect when there is an effect

Question 28

Beta

Answer 28

probability of a type II error

Question 29

Significant

Answer 29

when a result is very unlikely to occur when the null hypothesis is true

Question 30

Test Statistic

Answer 30

indicates that the sample data are converted into a single, specific statistic that is used to test a hypotheses

Question 31

Directional Test/ One-Tailed Test

Answer 31

statistical hypotheses specify either an increase or a decrease in the population mean

Question 32

Effect Size

Answer 32

provide a measurement of the absolute magnitude of a treatment effect

Question 33

Cohen’s d

Answer 33

measures mean difference in terms of the standard deviation

Question 34

Power

Answer 34

probability that the test will correctly reject a false null hypothesis

Question 35

Alpha Level

Answer 35

probability that the test will lead to a Type I error if the null hypothesis is true

Question 36

estimated standard error

Answer 36

an estimate of the real standard error when the value of σ is unknown

Question 37

t statistic

Answer 37

used to test hypotheses about an unknown population mean μ, when the vaule of σ is unknown

Question 38

degrees of freedom

Answer 38

describe the number of scores in a sample that are independent and free to vary

Question 39

t distribution

Answer 39

complete set of t values computed for every possible random sample for a specific sample size (n) or a specific degrees of freedom (df)

Question 40

estimated d

Answer 40

measure of effect size when population values are not known and you must substitute the corresponding sample values in their place

Question 41

r^2

Answer 41

percentage of variance accounted for by the treatment

Question 42

confidence interval

Answer 42

interval, or range of values, centered around a sample statistic