Biostats

Question 1

define mean

Answer 1

average of a set of observations

Question 2

define median

Answer 2

the middle most value in a set of values (unaffected by extreme values)

Question 3

define mode

Answer 3

most frequent value or values

Question 4

if the data is skewed to the left, this is also called?

Answer 4

negatively skewed

Question 5

if the data is skewed to the right, this is also called?

Answer 5

positively skewed

Question 6

when data is skewed, which method for finding the average is best?

Answer 6

the median and standard deviation

Question 7

when data is symmetric, which method for finding the average is best?

Answer 7

the mean and interquartile range

Question 8

define statistical inference

Answer 8

using stats to make inferences about a population based on data
collected using a sample from that population

Question 9

what is the null hypothesis?

Answer 9

states that there is no association/correlation/difference b/w 2 or more groups

Question 10

what is the alternative hypothesis?

Answer 10

indicates that there is an association/correlation/difference

Question 11

You cannot reject the null hypothesis if the observed t-value is between?

Answer 11

-2.1 and 2.1

Question 12

if the P-value is less than 0.05, what does this mean and how does it relate to the null hypothesis?

Answer 12

it is considered statistically significant and we can reject the null hypothesis

Question 13

if the P-value is more than 0.05, what does this mean and how does it relate to the null hypothesis?

Answer 13

it is considered non-significant and we can’t reject the null hypothesis

Question 14

what are terms we use for rejecting the null hypothesis when it is true

Answer 14

False positive, type 1 error (alpha)

Question 15

what are terms we use for not rejecting the null hypothesis when it is not true

Answer 15

false negative, type II error (beta)

Question 16

The larger the confidence level, the _____ our interval will be

Answer 16

wider

Question 17

define ordinal data, example?

Answer 17

Putting observations into categories which can be ranked in some way
Smoking status: current smoker, past smoker, never smoker
Socioeconomic status: low, middle, high

Question 18

define nominal data, example?

Answer 18

putting observations into categories with no order to the categories
History of depression 1=yes; 0=no
Smoking status: 1=current smoker, 0=nonsmoker