Chpts 11 - 15

Question 1

Two independent samples

Answer 1

sampling method is independent when the individuals selected for one sample do not dictate which individuals are to be in second sample.

Question 2

Two dependent samples

Answer 2

sampling method is dependent when the individuals to be selected in one sample are used to determine the individuals to be in the second sample.

Also called MATCHED-PAIR samples. Individuals CAN be matched against themselves.

Question 3

ANOVA

Answer 3

= Analysis of Variance.

An inferential method used to test the equality of three or more population means.

Question 4

P-Value

Answer 4

the probability of a statistic to be at least as far from the assumed value as the current observation

Question 5

In a one-way ANOVA test, if the P-Value < Level of Significance (alpha), then…

Answer 5

In a one-way ANOVA test, if the P value is less than or equal to the level of significance, reject the null hypothesis.

Comparing more than two population means, P-Value < Level of Significance (alpha) indicates that there are significant differences between at least two of the population means.

Question 6

In ANOVA method, n = ________ and k = _________.

Answer 6

In ANOVA method, n = total number of observations/subjects and k = number of groups.

Question 7

Assumptions for ANOVA procedure

Answer 7

Assumptions for ANOVA…

The samples must be assumed to be
- simple random samples;
- independent samples;
- normal populations;
- equal population standard deviations.

Question 8

In ANOVA method, the null hypothesis is that ____________________________ and the alternative hypothesis is that ________________________________.

Answer 8

In ANOVA method, the null hypothesis is that all the means of the groups are equal and the alternative hypothesis is that all the means are not equal.

Question 9

Correlation coefficients, r values…

Answer 9

Correlation coefficient of r=0 indicates no linear relationship exists between the variables.

Correlation coefficient of r=1 indicates the scatter plot contains points that all lie on a line with positive slope.

Correlation coefficient of r=-1 indicates the scatter plot contains points that all lie on a line with negative slope.

r^2 greater than or equal to 0.5 indicates a strong relation.
r^2 greater than or equal to 0.25, and less than 0.5 indicates a weak relation.
r^2 less than 0.25 indicates no relation.

Question 10

Linear Correlation Coefficient
or
Pearson Correlation Coefficient
(definition)

Answer 10

a measure of the strength and direction of the linear relation between two quantitative variables.

r represents sample correlation coefficient.
p (rho) represents population correlation coefficient.

Question 11

Confidence interval vs. prediction interval

Answer 11

A confidence interval is around the mean of a population.
A prediction interval is for selecting an individual from the population.

Question 12

parametric statistical procedures

Answer 12

inferential procedures that assume some underlying distribution (ex. normal distribution).

Question 13

nonparametric statistical procedures

Answer 13

inferential procedures that make no assumptions about the underlying distribution. Distribution-free procedures.