exam 1

Question 1

sample error definition

Answer 1

deviation between population and sample

Question 2

three major causes of sample error

Answer 2

• small sample size
• sample bias
• non-independence

Question 3

small sample size description

Answer 3

when you take a small sample, you may miss variation & it is always smaller than population size.

Question 4

sample bias description

Answer 4

doesn’t represent entire population

Question 5

non-independence description

Answer 5

• when you measure the same person or thing more than once
• or pseudo-replication

Question 6

confidence interval

Answer 6

more obvious than standard error

Question 7

standard error of mean

Answer 7

standard deviation/sample size

Question 8

Confidence intervals

Answer 8

gives a range around the sample mean in which the population mean should fall.

Question 9

if the mean is 65 days and the confidence interval is 25 days. where does the true population mean fall?

Answer 9

• 65-25=40
  *65+25=90

Question 10

observational studies

Answer 10

• look for patterns in naturally occurring variation to test a hypothesis
• always correlational
• should be 1st step

Question 11

experimental studies

Answer 11

• use carefully controlled experiments to test a hypothesis

Question 12

observational studies benefits and costs

Answer 12

• benefits: generally easier, faster, and cheaper. you don’t have to manipulate anything
• costs: knowing two variables are related does not tell you how or why. cannot understand cause and effect

Question 13

blank

Answer 13

control for the absorptions

Question 14

wild-type

Answer 14

this is whats common in that population

Question 15

sham

Answer 15

acts as placebo
- still does the same procedure without adding anything new

Question 16

vehicle

Answer 16

• administered using other mediums
• could be the saline making an effect and not the drug in an IV

Question 17

placebo

Answer 17

• prevents patient from knowing if they are getting a drug or fake drug
• researchers also do not know

Question 18

placebo effect

Answer 18

cortisol is a immunosuppressant
- it can effect the immune system just by thinking

Question 19

variable

Answer 19

• anything you are measuring or manipulating

Question 20

independent variable

Answer 20

cause
- factor
- predictor
- explanatory variable

Question 21

dependent variable

Answer 21

effect

Question 22

covariate

Answer 22

• like independent variable but you aren’t worried about how it changes itself
• ex. light changes so we worry about levels of light that effects the plant

Question 23

response variable

Answer 23

• will create variation

Question 24

continuous

Answer 24

• every value within the designated range is possible
• can be plot on a scale
• independent variable

Question 25

categorical

Answer 25

- not numerical; discrete groupings - cannot use mean - dependent variable

Question 26

ordinal

Answer 26

somewhere in between; categorical with an ordering structure - low, med, high - things that cannot be used in categorical, can be used here

Question 27

replication

Answer 27

- you need to have a sample size bigger than 1 - minimizes sample error

Question 28

power

Answer 28

the likelihood of rejecting a truly false null hypothesis given a specific sample size and effect size - should be able to reject null hypothesis at least 80%

Question 29

pseudo replication

Answer 29

- researchers think their data is independent and treat it like such - has really bad controls - fake

Question 30

what is central tendency?

Answer 30

the average

Question 31

what are the 3 major measures of central tendency we have discussed so far?

Answer 31

mean, median, mode

Question 32

mean

Answer 32

common average

Question 33

median

Answer 33

number that divides high and low on the scale

Question 34

mode

Answer 34

the most common value that appears

Question 35

difference between inferential and descriptive statistics?

Answer 35

inferential: used to test hypothesis. last step will be calculating p-value descriptive: used to summarize data and point out important trends, what the avg is like

Question 36

what is the probability of flipping a coin 3 times and getting heads all three times?

Answer 36

12.5%

Question 37

what is the probability of flipping a coin 3 times and getting heads atleast once?

Answer 37

7/8

Question 38

compute the descriptive statistics for the set of numbers below 2,8,10,15,15,15,30

Answer 38

mode: 15 median: 15 mean: 13.57 summation: 453.73 variance: 75.62 Standard deviation: 8.69 standard error:3.28

Question 39

a drug trial is underway to determine whether or not a drug slows the growth of cervical tumors. what is the null hypothesis for the drug?

Answer 39

the drug has no effect on the growth of the tumor

Question 40

what does the p-value directly quantify?

Answer 40

- the probability of a false positive if the null is rejected

Question 41

of all the emasurements of central tendency, the ___. is the most sensitive to outliers/ zeroes

Answer 41

mean