Behaviorial Science/Biostats

Question 1

power of a study increases w/

Answer 1

increased sample size, expected effect size, precision management

Question 2

power =

Answer 2

1 - beta

beta = stating there ISN’T an effect/difference when ONE EXISTS

Question 3

sensitivity =

Answer 3

test detects dz when dz present; screening test (rule out a dz)

1 - FN rate
TP/(TP + FN) aka TP/total dz +
a/(a+c)

Question 4

specificity =

Answer 4

test indicates NO DZ when dz actually absent; confirmatory test (rule in a dz)

1 - FP rate
TN/(TN+FP) aka TN/total dz negatives
d/(b+d)

Question 5

PPV

Answer 5

person WITH dz tested positive in test
TRUE POSITIVE!!

TP/(TP+FP)
a/(a+b)

high pretest probability = high PPV

Question 6

NPV

Answer 6

person WITHOUT dz who tested negative in test
TRUE NEGATIVE!!

TN/(FN+TN)
d/(c+d)

high pretest probability = LOW NPV

Question 7

incidence

Answer 7

of new cases

Question 8

prevalence

Answer 8

incidence x time

looks at ALL current cases –> tx that prolongs survival INCREASES prevalence

Question 9

odds ratio (OR)

Answer 9

used in case-control studies
odds that group w/ dz exposed to risk factor divided by odds that group w/o dz exposed to risk factor = (a/c)/(b/d) =

ad/bc

Question 10

relative risk (RR)

Answer 10

used in cohort studies
risk of developing dz in exposed group divided by risk in unexposed group

[a/(a+b)]/[c/(c+d)]

if low prevalence –> RR = OR

Question 11

attributable risk

Answer 11

difference in risk b/w exposed/unexposed groups

Attributable Risk % = (RR - 1)/RR
[a/(a+b)] - [c/(c+d)]
event rate(of tx) - event rate(in other group)

Question 12

Absolute risk reduction (ARR)

Answer 12

AR(in control) - AR(w/ tx)

[c/(c+d)] - [a/(a+b)]

Question 13

needed to treat

Answer 13

pts needed to treat for 1 pt to benefit

1/ARR

Question 14

needed to harm

Answer 14

of pts who need to be exposed to RF for 1 pt to be harmed

1/attributable risk

Question 15

relative risk reduction (RRR)

Answer 15

[AR(control) - AR(tx)]/AR(control)

Question 16

type 1 error (alpha)

Answer 16

stating there IS an effect when there ACTUALLY IS NOT (mistakenly reject null hypothesis)

b/(b+d)

Question 17

type II error (beta)

Answer 17

stating there IS NOT an effect when there ACTUALLY IS (fail to reject null hypothesis)

c/(a+c)

Question 18

95% confidence interval Z-score =

Answer 18

1.96

Question 19

99% confidence interval Z-score =

Answer 19

2.58

Question 20

standard error of mean (SEM) =

Answer 20

SD/(sq rt of n)

SD (standard deviation) = aka sigma
n = sample size

Question 21

formula to obtain confidence limits

Answer 21

mean +/- [Z-score x SEM]

Question 22

wave seen in awake stage?

Answer 22

beta (highest freq, lowest amp)

Question 23

wave seen in relaxation stage?

Answer 23

alpha

Question 24

wave seen in N1 stage?

Answer 24

theta

Question 25

wave seen in N2 stage?

Answer 25

sleep spindles and K complexes

Question 26

wave seen in N3 stage?

Answer 26

delta (lowest freqm highest amp)

Question 27

wave seen in REM?

Answer 27

beta

Question 28

what stage of sleep does night terrors, bedwetting, sleep walking occur

Answer 28

N3 - NO memory of sleep terror (as opposed to REM)

Question 29

REM occurs due to what part of brain

Answer 29

PPRF (paramedian pontine reticular formation)

Question 30

REM stage ass w/?

Answer 30

dreaming
loss of motor tone
erections
increased brain O2 use

Question 31

sleep stage w/ bruxism (teeth grinding)

Answer 31

N2

Question 32

sleep enuresis preferred tx

Answer 32

DDVAP (oral desmopressin acetate)

preferred over imipramine, indomethacin

Question 33

key NT changes in REM sleep

Answer 33

increased ACh

NE reduces REM sleep

Question 34

primary sleep stage in narcolepsy

Answer 34

straight to REM sleep

Question 35

tx for narcolepsy

Answer 35

modafinil, amphetamines (stimulants)
sodium oxybate (GHB) - for nighttime

Question 36

NT change in narcolepsy

Answer 36

decreased hypocretin-1 from lateral hypothalamus