Assignment 5

Question 1

Nominal Scale

Answer 1

A nominal level of measurement is simply a matter of distinguishing by name, e.g., 1 = male, 2 = female. Even though we are using the numbers 1 and 2, they do not denote quantity.

Question 2

Ordinal Scale

Answer 2

An ordinal scale indicates direction, in addition to providing nominal information. Low/Medium/High; or Faster/Slower are examples of ordinal levels of measurement.

Question 3

Interval Scale

Answer 3

Interval scales provide information about order, and also possess equal intervals.

Question 4

Ratio Scale

Answer 4

In addition to possessing the qualities of nominal, ordinal, and interval scales, a ratio scale has an absolute zero (a point where none of the quality being measured exists).

Question 5

Student’s t-Test for Independent Samples

Answer 5

A calculation that tests the hypothesis that two sample means point to (or estimate) the same population mean. The term “independent” indicates that each subject is in one and only one sample.

Question 6

Student’s t-Test for Related Samples

Answer 6

A calculation that tests the hypothesis that a sample mean of measurement differences points to (or estimates) a population mean of zero. The term “related” indicates that subjects act as their own control or that two different subjects have been matched or linked in some way. Two measurements are collected per subject or pair and the sample mean is computed by subtracting one from the other.

Question 7

Sampling Distribution for the Difference of two Sample Means

Answer 7

A sampling distribution which is formed by selecting two random samples of equal size from the same population and then constructing a distribution of the differences of the means in each sample. This sampling distribution reveals what the difference between two sample means is expected to be when no treatment effects are present.

Question 8

Standard Error for the Difference of Means

Answer 8

The standard deviation of the differences in sample means used to form a Sampling Distribution for the Difference of Two Means.

Question 9

Pooled Variance

Answer 9

The average of the variances of two independent samples for estimating the variance of a measurement in a population.

Question 10

Central Limit Theorem

Answer 10

Given certain conditions, the arithmetic mean of a sufficiently large number of iterates of independent random variables, each with a well-defined (finite) expected value and finite variance, will be approximately normally distributed, regardless of the underlying distribution

Question 11

Homogeneous Variance

Answer 11

The assumption that the variability of measurements is similar among all study groups.

Question 12

Heterogeneous Variance

Answer 12

The assumption that the variability of measurements is different among all study groups.

Question 13

Satterthwaite Adjustment

Answer 13

The calculation that is done for an independent samples Student t-Test when the homogeneity of variance assumption is violated.

Question 14

One-tail test

Answer 14

A test of statistical significance in which the rival hypothesis is stated in one direction.

Question 15

Two-tail test

Answer 15

A test of statistical significance in which the rival hypothesis is not stated in any particular direction.

Question 16

Non-Parametric (Rank Sum) Tests

Answer 16

A class of tests of hypotheses that make no or few assumptions about the nature of a population distribution.

Question 17

Mann-Whitney U Test

Answer 17

Non-parametric alternative test to the independent sample t-test. It does not assume normal distribution.

Question 18

Wilcoxon Signed Ranks Test

Answer 18

A non-parametric statistical hypothesis test used when comparing two related samples, matched samples. To be used in place of a student’s t-test for related samples for non-normal distributions.