Defining the Data

Question 1

What is a population?

Answer 1

The collection of all the individuals of interest

Question 2

What is a sample?

Answer 2

The subset of the population that is selected as the

result of sampling

Question 3

What is a biased sample?

Answer 3

Study participants are not representative of the target population

Question 4

What is an unbiased sample?

Answer 4

Study participants are representative of the target population

Question 5

What is validity?

Answer 5

the extent to which the instruments that are used in the study measure exactly what they should be measuring

Question 6

What is reliability?

Answer 6

the extent to which the results of the study are consistent when the study is repeated under the same conditions

Question 7

What is a variable?

Answer 7

something whose value can change or vary

Question 8

What is data?

Answer 8

the values we obtain when we measure a variable

Question 9

What are the two type of variables?

Answer 9

1, Categorical “attributes”

2. Quantitative “numbers”

Question 10

What are the two types of categorical attributes? And their meanings?

Answer 10

Nominal: Values are “names” that are unordered categories
Ordinal: Values are “names” that are ordered categories

Question 11

What are the two types of quantitative numbers? And their meanings?

Answer 11

Discrete: Values are integer values 0, 1, 2 … on a proper numeric scale
Continuous: Values are a measured number of units, including possible decimal values

Question 12

What are the two types of “continuous” quantitative numbers? And their meanings?

Answer 12

Interval: Interval scale variable has no true zero on the scale
Ratio: Ratio scale variable has true zero on the scale (0 just means the absence of something)

Question 13

What is derived variables?

Answer 13

variables that you create by calculating or categorising variables that already exist in your data set

Question 14

What are the two different types of derived variables?

Answer 14

Calculated

Categorized

Question 15

What is threshold variables?

Answer 15

variables obtained by splitting the values of another variable into categories based on the values of well-known thresholds

Question 16

What is a transformed variable?

Answer 16

a variable which has been transformed from another variable with a different measurement scale (ex. square rooting numbers, squaring…)

Question 17

What is an exposure variable?

Answer 17

a variable thought to predict an outcome variable

Question 18

What is an outcome variable?

Answer 18

a variable thought to change as a function of changes in an exposure variable

Question 19

What is the Center?

Answer 19

A representative or average value that indicates where the middle of the data set is located

Question 20

What is variation in data?

Answer 20

A measure of the amount that the values vary among themselves from the average value

Question 21

What is distribution in data?

Answer 21

The nature or shape of the distribution of data (such as bell-shaped, uniform, or skewed)

Question 22

What are outliers in data?

Answer 22

Sample values that lie very far away from the vast majority of other sample values

Question 23

What is time in data?

Answer 23

Changing characteristics of the data over time

Question 24

What are the measures of central tendency?

Answer 24

Means, medians & modes

Question 25

What is the central tendency?

Answer 25

the tendency for values in a group to cluster around a central or 'average' value which is typical of the group

Question 26

do extreme values affect the median?

Answer 26

Nope

Question 27

Do extreme values affect the mean?

Answer 27

Yep

Question 28

Do extreme values affect the mode?

Answer 28

Nope

Question 29

What is dispersion? (variability, scatter, spread)

Answer 29

how stretched or squeezed a distribution of values within a sample or a dataset is

Question 30

which percentiles are good summary of a sample?

Answer 30

the “Five Number Summary” (P0, P25, P50, P75, P100)

Question 31

what are the measures of dispersion

Answer 31

Range, interquartile range, and standard deviation

Question 32

What does a small standard deviation mean?

Answer 32

most data points are close to the mean

Question 33

What does a large standard deviation mean?

Answer 33

data points are widely spread from the mean

Question 34

What is a percentile?

Answer 34

is a measure that indicates the value below | which a given percentage of observations in a group of observations fall

Question 35

How do you calculate the IQR (interquartile range)?

Answer 35

Q3 - Q1

Question 36

What is Q1?

Answer 36

25%

Question 37

What is Q3?

Answer 37

75%

Question 38

What is the formula of median when the sample is odd?

Answer 38

[𝑛+1]/2

Question 39

What is the formula of median when the sample is even?

Answer 39

([𝑛/2] , [𝑛/2+ 1])

Question 40

A garden contains 39 plants. The following plants were chosen at random, and their heights were recorded in cm: 38, 51, 46, 79, and 57. Calculate their heights’ standard deviation.

Answer 40

https://byjus.com/maths/standard-deviation-questions/

Question 41

SD indicates the variation where the what is the measure of central tendency?

Answer 41

Mean

Question 42

IQR indicates the variation where the what is the measure of central tendency?

Answer 42

median

Question 43

What is inferential statistics?

Answer 43

statistics used to make inferences based on relationships found in the sample to relationships truly exist in the population

Question 44

What is Descriptive statistics?

Answer 44

statistics used to describe, show or summarize data | in a meaningful way (take pictures of data)

Question 45

What are the two types of statistics?

Answer 45

descriptive statistics and inferential statistics

Question 46

What is a theory?

Answer 46

a generalization about a phenomenon (explanation of how or | why something occurs)

Question 47

What is a hypothesis?

Answer 47

a proposed explanation made on the basis of limited evidence as a starting point for further investigation (without any assumption of its truth)

Question 48

What are the steps of the research process?

Answer 48

1. Initial observation (Research question) 2. Generate theory 3. Generate hypothesis 4. Collect data to test hypothesis 5. Analyse data

Question 49

Why is data important?

Answer 49

 Identifying problems  Planning & making informed decisions  Monitoring/evaluating progress  Test hypotheses & make inferences about populations of interest

Question 50

What is the formula to calculate percentages?

Answer 50

L = sample size [𝑑𝑒𝑠𝑖𝑟𝑒𝑑 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑖𝑙𝑒/100] If L is whole number use average of the L and (L+1). If L is not whole number round to the next whole number