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Question 1

what is postive control group should have

Answer 1

should show a particular change during the experiment

Question 2

postive control

Answer 2

a group in an experiment that receives a treatment with a known result, there fore should show a particular change during the experiment

Question 3

positive control group is used for

Answer 3

1used to asses test validity so to asses a new test’s ability to setect a disease = sensitivity
2Used to control for unknown variables during experiment
3to give the scientist something to compare with the test group

Question 4

negative control are

Answer 4

groups where no phenomenon is expected, they ensure that there is no effect when there should be no effect

Question 5

postive and negative control group are used for

Answer 5

Used to eliminate most potential confounding variables

Question 6

Vehicle control

Answer 6

is a solution that contains everything but the test substance you are evaluating

Question 7

characterise of vehicle control

Answer 7

Often times you may need to use solubilizing factor or reduced pH or ethanol to solubilize your drug

Question 8

Sham or procedural control

Answer 8

a control that has the exact same procedure performed without the factor be evaluated

Question 9

how to overcome Sham ethical issue

Answer 9

In many clinical trials you can run a comparative effectiveness study where you compare your new drug or procedure to the current standard of care.

Question 10

Complete Randomized Design

Answer 10

All subjects are assigned randomly to a group or groups and then the IV is randomly assigned to each group.

Question 11

Factorial Designs

Answer 11

One of the more common designs used in experiments. The simplest being a comparison between a treatment and a control. This would be a 1 x 2 factorial design

Question 12

. Traditional dose-response curve is

Answer 12

a 1 x 6 factorial design

Question 13

Factorial designs can also examine

Answer 13

the effects of more than one IV (called factors) simultaneously.

Question 14

what is the thing that can be a factor?

Answer 14

Essentially anything that can be discretely identified can be a factor (dose, time, type of treatment

Question 15

Repeated Measures Design (within subjects design)

Answer 15

The same test is performed multiple times on the same subject

Question 16

Repeated Measures Design required

Answer 16

Special statistical analyses

the data is no longer completely random.

Question 17

Randomized blocks designs

Answer 17

Similar to completely randomized designs except that blocks of subjects are generated or self-select, and then the blocks are assigned randomly across the factors

Question 18

block

Answer 18

group of experimental units are similar ,

Question 19

bock are important in

Answer 19

decrease the variability within each group , which allows us to detect differences caused by the treatments more clearly

Question 20

types of experimental designs

Answer 20

completely randomized design, randomized block design , matched pairs design

Question 21

a stratified, randomized block design

Answer 21

If there is an inherent level involved in the randomized block design

Question 22

Matched Samples design.

Answer 22

A special case of repeated measures where two different groups are pre-matched to be as identical as possible.

Question 23

This pre-matching introduces

Answer 23

a bias and is therefore treated statistically as a special case of repeated measures

Question 24

advantage of Repeated measures

Answer 24

reduces within subjects variability
thereby increasing precision and power
leading to a reduction in the number of subjects.

Question 25

Three major disadvantages of repeated measures

Answer 25

1- practice effects (only the first test is immune).
2- Differential carry over effects. Prior exposure affects subject in second exposure one way and a different way under another condition.
3- Statistical issues often assume total independence to meet the criteria of randomness (the basic probability o which al stats are based). Since they are repeated measures, randomness is impossible

Question 26

practice effects overcome

Answer 26

This problem is overcome by counterbalancing. Practice effects affect all treatment conditions equally.

Question 27

Repeated measures cross over design/two period two treatment design

Answer 27

Repeated measures designs are threatened by
carry-over effects, practice effects, and priming.
There is often a washout period (especially true with drug studies).

Question 28

multiple blocks of experimental units and worried about sequence or carry over effects that could threaten the design

Answer 28

. You can randomize blocks,

or alternatively using a Latin Square.