Lab Quiz

Question 1

What is a Retrospective Study?

Answer 1

retrospective studies can take advantage of a larger sample size by looking at data that has already been collected

Question 2

What is a Prospective study?

Answer 2

prospective studies incorporate better controls over conditions, producing greater validity, predictive power, and cost

Question 3

Single Blind vs Double blind study

Answer 3

In a single-blind study, only the participants are blinded (i.e don’t know which group they are in). In a double-blind study, both participants and experimenters are blinded

Question 4

What is the null hypothesis

Answer 4

predicts a condition or treatment will have no effect, or there will be no difference between treatments.

Question 5

what is the alternative hypothesis?

Answer 5

there will be a measurable effect as a result of tx

Question 6

do you ever prove a hypothesis is true?

Answer 6

No - you can only accept or reject the null hypothesis

Question 7

define Independent Variable

Answer 7

“treatment variable” is the one
controlled by the researcher; i.e. treatment(s) you are applying, groups you are testing. Categorical, or continuous numerical.

Question 8

define Dependent Variable

Answer 8

“response variable” is the
condition that changes in response to the independent
variable; what you are actually measuring.

Question 9

define Controlled Variables

Answer 9

Variables that need to be held
constant to isolate the effects of the experimental treatment (tying to avoid a “confounding effect”).
ex: temperature held constant

Question 10

What things need to be considered when designing an experiment?

Answer 10

Population of interest, levels of tx, control tx, # of replications, and potential sources of error

Question 11

What is the Nuremberg Code?

Answer 11

The Nuremberg Code (1946) is the most important ethical standard in medical research. Has 10 elements including consent, experiments for the greater good of society, etc.

Question 12

How to calculate a test statistic?

Answer 12

(difference between groups)/(difference within groups)

Question 13

define p value

Answer 13

p is defined as the probability of getting the test statistic you did, or one more extreme, given the null hypothesis is true.

Question 14

How do you determine significance of a test statistic?

Answer 14

Compare p to ⍺ to determine significance

If p > ⍺, we fail to reject the null hypothesis
tx has no effect

Question 15

When do you reject the null hypothesis?

Answer 15

If p < ⍺, we reject the null hypothesis and conclude that there is a
significant difference between the groups

Question 16

When do you fail to reject the null hypothesis?

Answer 16

If p > ⍺, we fail to reject the null hypothesis

Question 17

When do you use a t-test?

Answer 17

A t-test can only be used when comparing the means of two groups - often used in hypothesis testing to determine whether a process or treatment actually has an effect on the population of interest, or whether two groups are different from one another.

Question 18

When do you use ANOVA?

Answer 18

when you have 2 or more groups

Question 19

When would you perform correlation analysis?

Answer 19

to discover if there is a relationship between two variables/datasets, and how strong that relationship may be

Question 20

Correlation vs Linear Regression

Answer 20

Correlation: based on sample data of both x and y
Determines strength of relationship

Linear regression: researcher picks the x values
Allows for prediction of y based on values of x

Question 21

Define sensation

Answer 21

Change in frequency of action potentials by sensory receptor cells in response to stimulation.

Question 22

define perception

Answer 22

Interpretation at the sensory cortex of action potentials released due to sensation.

Your body is constantly sensing all sorts of changes, but your conscious brain only perceives some of those changes.

Question 23

define the frequency code

Answer 23

frequency of APs arriving at the sensory cortex from a single receptor

Question 24

define population code

Answer 24

of same receptors sending APs to the sensory cortex in response to a stimulus

Question 25

define sensory acuity

Answer 25

The ability to identify (discern) the type, the strength and location of separate sensations in perception.

Question 26

What influences sensory acuity?

Answer 26

• Magnitude of the stimulus (“frequency code”)
• Number of receptors activated and receptive field size (“population code”)
• Degree of receptive field overlap (convergence)
• Amount of sensory cortex devoted to interpreting APs
• Lateral inhibition

Question 27

if you have a large receptive field, is it more or less sensitive?

Answer 27

larger = more sensitive

Question 28

if you have a small receptive field, is it more or less sensitive?

Answer 28

smaller = less sensitive

Question 29

define a receptive field

Answer 29

Area of body surface where a stimulus causes a sensory neuron to fire

Question 30

what influences receptive field size?

Answer 30

convergence in the sensory pathway

Question 31

more convergence = more or less acuity?

Answer 31

more convergence = less acuity

Question 32

How does lateral inhibition effect sensory acuity?

Answer 32

lateral inhibition increases sensory acuity

Question 33

define projection

Answer 33

Projection is the brain’s ability to localize the source of stimulation- i.e. The “feeling” that your brain projects onto the location where the stimulation is occurring.

Question 34

What is the purpose of sensory adaptation?

Answer 34

it blocks redundant stimuli at the receptor (i.e. a decrease in receptor activity –> reduced APs)

Question 35

Role of semicircular canals

Answer 35

dynamic equilibrium; detect rotation

Question 36

role of utricle and saccule

Answer 36

static equilibrium; detect linear acceleration/deceleration

Question 37

what is endolymph

Answer 37

a viscous fluid that surrounds cupula that is very high in K+

Question 38

Explain endolymph’s role in changes of motion

Answer 38

Endolymph resists changes in motion (inertia); stimulating hair cells when rotation begins AND ends

Question 39

what does a post-rotational nystagmus provide evidence for?

Answer 39

Post-rotational nystagmus provides evidence of vestibular modification to skeletal muscles

Question 40

define role of hair cells in a vestibular apparatus

Answer 40

Hair cells are tonic receptors that change their rate of firing based on K+

R & L vestibular inputs are equal when not moving; differences between R & L are interpreted as motion

Question 41

explain the importance of the kinocilium

Answer 41

This is the tallest of the stereocilia (hair cells) and provides orientation.
If tips of the hair cells bend toward the kinocilium, the channels are open. – higher rate of APs.
If tips are bending away from kinocilium, channels close – no APs occur

Question 42

define Control treatment

Answer 42

(if needed)- When the independent variable is eliminated or held constant. Something to compare to.

Question 43

Explain the Belmont Report of 1979

Answer 43

• Established the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research
• Current Federal regulations for the protection of human research participants are based on the Belmont Report
1. Respect for Persons (autonomy)
Each person treated as an autonomous agent

              Persons with diminished autonomy may need additional protections
2. Beneficence 
             Maximize possible benefits and minimize 
              possible harm 
3. Justice
              risks and benefits fairly applied without bias