Module 3: Descriptive Statistics

Question 1

Variable

Answer 1

-any measurable characteristic of an observation unit and contains 3 pieces of information
1. what the variable represents (long jump distance)
2. measurement unit (cm)
3. description of observation unit (student)

Question 2

Numerical variables

Answer 2

-data is numeric

Question 3

Categorical variables

Answer 3

-data is a qualitative description

Question 4

Continuous numerical variable

Answer 4

-can take on continuous numbers, including factors (104.23 kg)

Question 5

Discrete numerical variable

Answer 5

-can only take on whole numbers (25 people)

Question 6

Ordinal categorical variable `

Answer 6

-can take on qualitative values but where values are from a ranked scale (on a scale of 1-5 how happy are you)

Question 7

Nominal categorical variable

Answer 7

-can take on qualitative values but where values do not have any particular order

Question 8

Counts

Answer 8

-number of sampling units in each category (number)

Question 9

Proportions

Answer 9

-the share of the total sampling units in each category (percentage)

Question 10

Central tendency

Answer 10

-describes typical value in your sample (mean) using counts and proportions

Question 11

Dispersion

Answer 11

-describes the spread of the values

Question 12

Quartiles

Answer 12

-sort data in your sample from lowest to highest value
-find second quartile by splitting data in half
-find first quartile by creating a subset that is the lower half of the values and splitting that in half
-find third quartile by doing this but with upper values

Question 13

Central tendency

Answer 13

-given by the second quartile (median)

Question 14

Interquartile range

Answer 14

-between the first and third quartiles

Question 15

Effect size

Answer 15

-change in mean value of the response variable among groups and it allows us to put study results into context

Question 16

Calculating effect size

Answer 16

-difference calculations: difference in mean values among groups (starbs coffee is $2.10 and tims is $1.79, so starbs coffe is $0.31 more expensive0
-ratio calculations: ratio of mean values among groups ($2.10/$1.79= 1.17, so 17% more expensive)