summary stats

Question 1

variable

Answer 1

any factor, trait, or condition that can exist in different amounts or types of

Question 2

main 3 kinds of variables

Answer 2

independent, dependent, controlled

Question 3

independent variable

Answer 3

one that is changed by the experiment

Question 4

dependent variable

Answer 4

the things that the scientist focuses their observations on to see how they respond to the change made to the independent variable

Question 5

controlled variable

Answer 5

the variable that remains constant and unchanging

Question 6

kinds of variables within the mains

Answer 6

measurement (continuous, discontinuous)
ranked
attributes

Question 7

continuous variables

Answer 7

a quantitative variable that has an infinite number of possible values that aren’t countable
(height, weight, temperature)

Question 8

discontinuous variable

Answer 8

has fixed numerical values with no intermediate values possible
(# of eggs, # of vertebrae)

Question 9

ranked variables

Answer 9

cannot be measured but can be ordered or ranked by their magnitude
(ordinal variables)

Question 10

attributes

Answer 10

just names, cannot be measured or ranked (nominal, categorical, qualitative variables)

Question 11

data (plural of datum)

Answer 11

counts or measurements used to address scientific questions

Question 12

population

Answer 12

all members of a defined set of entities of interest

Question 13

sample

Answer 13

a subset of a population of manageable size

Question 14

sample size

Answer 14

the number of observations in a sample, denoted as n

Question 15

summary statistics

Answer 15

descriptive communication of scientific data

Question 16

2 main categories of summary statistics

Answer 16

measures of central tendency
measures of variability

Question 17

measures of central tendency

Answer 17

the middle of a data sample
(mean, median,mode)

Question 18

measures of variability

Answer 18

show how much your data points vary from each other or the average
how variables are spread out, how scattered around the middle the data is
(range, variants, standard deviation)

Question 19

mean

Answer 19

one measure of central tendency
“the average”

Question 20

advantages of the mean (3)

Answer 20

easy algebraic description
easy to calculate
fits in with other standard statistical techniques

Question 21

disadvantages of the mean

Answer 21

is influenced by outliers
may be in a shoulder and not at a peak or may not exist in data

Question 22

median

Answer 22

2nd measure of central tendency
“the middle”

Question 23

advantage of the median

Answer 23

not affected by extreme values

Question 24

disadvantage of the median

Answer 24

no easy algebraic calculation

Question 25

variance

Answer 25

a measure of variability or scatter the spread of the data values around the middle “mean squared deviation”

Question 26

what is the square root of variance

Answer 26

the standard deviation (s) **

Question 27

advantages of variance

Answer 27

easy algebraic description fits in with standard statistical procedures

Question 28

disadvantages of variance

Answer 28

very sensitive to extreme values units are square of measured units and thus aren’t easily interpretable

Question 29

5 Steps of calculating variance (Standard deviation)

Answer 29

1. Calculate mean of data 2. Subtract mean from each (n) 3. Square the numbers of each 4. Find the mean of the squared numbers 5. Divide mean by n-1 or take the square root of the mean of the squared #s

Question 30

Interquartile range (IQR)

Answer 30

The middle 50% of values when ordered from least to greatest The difference between Q1 and Q3

Question 31

How to find the IQR

Answer 31

1. Find the median of the lower (Q1) and upper half (Q3) of the data 2. Find the difference between Q1 & Q3

Question 32

Coefficient of Variation (CV)

Answer 32

CV= s/mean often expressed as a percentage allows to compare 2 data sets when the units are different

Question 33

Bias (accuracy)

Answer 33

the difference between the average of a large set of estimates and the true population value

Question 34

precision

Answer 34

variability among estimates of the same true value