Sociology Exam 3

Front 1

Hypothesis?

Back 1

A statement that you set out to prove.

Front 2

Null Hypothesis?

Back 2

A null hypothesis is the hypothesis that is tested. It can be a statement of no difference, a statement of chance, or a statement of no relationship.

Front 3

Extreme Score or Value?

Back 3

A score or a value that has a low probability of occurrence.

Front 4

Significant Difference?

Back 4

One that is so great that it has a low probability of having occurred by chance.

Front 5

What is the central question surrounding a hypothesis test involving a single sample mean and a population mean?

Back 5

The central question is whether the difference between the two means is extreme -- whether the difference is significant.

Front 6

What does it mean to reject the null hypothesis?

Back 6

To reject the null hypothesis is to reject the idea that the sample mean came from a population having a mean of ___________, such as in the flextime worker example: 193.80

Front 7

What levels of significance are commonly used by statisticians?

Back 7

The .05 and .01 levels of significance.

Front 8

Calculated Test Statistic?

Back 8

(Our result) If it meets or exceeds the critical value, then we can legitimately think of our observed difference as being extreme.

Front 9

Critical Region?

Back 9

The portion of the sampling distribution (such as the sampling distribution of Z) that contains all the values that allow you to reject a null hypothesis.

Front 10

How are the critical value and the critical region related?

Back 10

The critical value is the beginning of the critical region. If our calculated test statistic meets or exceeds the critical value, thereby falling into the critical region, we are in a position to reject the null hypothesis.

Front 11

Type 1 Error?

Back 11

Sometimes referred to as an "alpha error."

It is a rejection of the null hypothesis when the null is, in fact, true.

Front 12

What is the definition of a Type 1 error?

Back 12

A Type 1 error is the rejection of the null when, in fact, it is true.

Front 13

Level of Significance?

Back 13

An expression of the probability of making a Type 1 or alpha error.

Front 14

What is the probability of making of a Type 1 error?

Back 14

The probability of making a Type 1 error is equal to the level of significance (the alpha level).

Front 15

Type 2 Errors?

Back 15

(Or Beta) The failure to reject the null when it is false.

Front 16

In a single sample hypothesis test, what is the difference in the procedures when sigma is unknown as opposed to when sigma is known?

Back 16

When sigma is unknown, the standard error of the mean is estimated and t is used. When sigma is known, the standard error of the mean is calculated in a direct fashion and Z is used.

Front 17

To say that two samples are Matched or Related?

Back 17

In some way is to say that the cases included in the samples were not selected independently of one another.

Front 18

What are matched or related samples?

Back 18

Matched or related samples are samples involving cases or subjects that share certain characteristics in common.

(Example: Using the same sample -- or group -- twice, in two or more different measures)

Front 19

In this application (pg. 183), how do you calculate the d values?

Back 19

Find the difference between the two scores or values associated with a given research subject or case.

Front 20

What is the definition of the estimate of the standard error in the case of a t test for related sample means?

Back 20

It is an estimate of the standard deviation of the sampling distribution of mean differences.

Front 21

How is the estimate of the standard error calculated in the case of a t test for related sample means?

Back 21

The standard deviation of the distribution of differences (in other words, the distribution of the d values) is divided by the square root of n.

Front 22

What does the value of t represent in the t test for related sample means?

Back 22

The t value is the calculated test statistic. It is a ratio that expresses how far the observed mean difference departs from the assumed mean difference of 0 in standard error units.

Front 23

Independent Samples?

Back 23

The idea that the sample of fraternity members is selected independently of the sample of non-members.

OR

Samples that are not linked experimentally and the measurement of one sample has no effect on the others.

Front 24

What does the phrase "independent samples" mean?

Back 24

Independent samples are samples selected in such a way that the selection of cases or subjects included in one sample has no connection to or influence on the selection of cases or subjects in the other sample.

Front 25

In the t test for difference of means for independent samples, which difference is the object of interest?

Back 25

The test focuses on the difference between the mean of one sample and the mean of another sample, with an eye toward the extent to which any observed difference represents a true difference between population means.

Front 26

Standard Error of the Difference of Means?

Back 26

Page 194

Front 27

Probabilistic Distribution?

Back 27

Gives you a statement of probabilities associated with various portions of the curve.

Front 28

How do you identify the Critical Value?

Back 28

Calculate the Degrees of Freedom. Whether it is simply (n-1)
OR
(n1-1)+(n2-1)

Then look it up depending on the level of significance in Appendix B.

Front 29

What is the Critical Value at the .05 level of significance (beginning of Critical Region)?

Back 29

(+ or -)1.96

Front 30

What is the Critical Value at the .01 level of significance (beginning of Critical Region)?

Back 30

(+ or -)2.58

Front 31

What do you do if our Calculated Test Statistic falls within the Critical Region?

Back 31

You reject the Null Hypothesis.

Front 32

When you reject the Null Hypothesis and it is true, what type of error are you making?

Back 32

Type 1 Error

Front 33

What is the probability of making a Type 1 Error equal to?

Back 33

Level of Significance.

Front 34

When you fail to reject the Null Hypothesis and it is false, what type of error are you making?

Back 34

Type 2 Error

Front 35

What is Type 1 Error sometimes referred to as?

Back 35

Alpha Error

Front 36

What is Type 2 Error sometimes referred to as?

Back 36

Beta Error

Front 37

*What is the formula (explained) for calculating the test statistic?

Back 37

It is the (mean of a sample OR mean of the differences) minus (mu-mean of the population) divided by the (standard deviation of the mean OR standard deviation of the mean differences)

Front 38

The alpha level is also known as the __________?

Back 38

Level of Significance

Front 39

The most commonly used levels of significance are _______ and ______?

Back 39

.05 (95%) and .01 (99%)

Front 40

What is the formula (explained) for calculating the mean of the differences?

Back 40

It is the (sum of differences) divided by the (number of samples - n).

Front 41

What does the t value stand for?

Back 41

The calculated test statistic.

Front 42

In an Independent Sample, how is the Null Hypothesis stated?

Back 42

u1=u2 ..OR.. u1-u2=0

(Example: u1/members = u2/nonmembers; OR; u1/members - u2/nonmembers = 0)

Front 43

What is the square root of the variance?

Back 43

The Standard Deviation.

Front 44

True/False.
In a matched samples design (the test involving the mean difference) the number of cases in each sample must be equal.

Back 44

TRUE.

Front 45

True/False.
In the test for the difference of means, independent sample design, the number of cases in each sample must be equal.

Back 45

FALSE.

Front 46

In the matched samples design, the sampling distribution at issue is the sampling distribution of ____________?

Back 46

Mean Differences.

Front 47

In the independent samples design, the sampling distribution at issue is the sampling distribution of _____________?

Back 47

The difference between means.