Vocab review for test 11/8/18

Question 1

Observational Study

Answer 1

When we observe individuals and record data without intervention. They cannot demonstrate a cause-and-effect relationship.

Question 2

Experiment

Answer 2

When we randomly assign subjects to treatments. An experiment CAN demonstrate a cause-and-effect relationship.

Question 3

explanatory variable

Answer 3

The variable controlled by the experimenter. It attempts to EXPLAIN the results

Question 4

response variable

Answer 4

The variable that the experimenter is measuring for the outcome.

Question 5

confounding variable

Answer 5

A variable that may be responsible for the outcome. The experimenter is unable to tell if the results are because of the explanatory variable or the confounding variable

Question 6

Control Group

Answer 6

A group that receives no treatment or a placebo. It provides a baseline for comparison!

Question 7

Random assignment

Answer 7

When the experimenter randomly assigns subjects to the treatment or control group. The purpose of this is to create groups that are as much alike as possible.

Question 8

Random selection

Answer 8

When the experimenter randomly selects people to be in their experiment. The purpose is so that we can generalize from the sample to the population.

Question 9

Replication

Answer 9

Repeating the process/experiment on multiple subjects.

Question 10

Completely randomized experiment

Answer 10

All subjects are randomly assigned to the treatment group and control group.

Question 11

Randomized block experiment

Answer 11

Subjects are first separated into similar groups (blocks) and then within each group subjects are randomly assigned to the treatment and control groups.

Question 12

Matched pair experiment

Answer 12

When subjects are PAIRED together in some way that reduces variation and then assigned to the treatment or control group.

Question 13

y-intercept

Answer 13

The predicted value for “y” when “x”=0

Question 14

slope

Answer 14

predicted change in “y” for every 1 increase in “x”

Question 15

placebo

Answer 15

Something that is given to the subject so they don’t know if they are getting the treatment or the control (sometimes a sugar pill)

Question 16

single-blind experiment

Answer 16

When the subjects don’t know which treatment they are receiving but the experimenter does, or vice versa

Question 17

double-blind experiment

Answer 17

When the subjects and the researchers don’t know who is receiving which treatment

Question 18

correlation coefficient (r)

Answer 18

Describes the strength and direction of the data.

Question 19

Coefficient of determination (r-squared)

Answer 19

Give the % of the variability in “y” that can be explained by the model.

Question 20

z-score

Answer 20

Tells how many standard deviations the data point is above or below the average. z = (data point - average)/standard devation