Unit 1: Data Collection & Desciptive Statistics

Question 1

Hypotheses must be…

Answer 1

Testable and falsifiable

Question 2

In an equation, what is

n

Answer 2

Sample size

Question 3

In an equation, what is

Σ

Answer 3

Sum (add the values)

Σ is the capital Greek letter sigma

Question 4

In an equation, what is

x_i

Answer 4

Individual data points

Question 5

In an equation, what is

s or σ

Answer 5

Standard deviation

σ is the lower case Greek letter sigma

Question 6

In an equation, what is

SE_x̄

Answer 6

Standard Error of the Mean (also called “standard error”)

Question 7

In an equation, what is

x̄

Answer 7

Mean

Pronounced “x bar”

Question 8

Explaining the meaning of:

x̄

Answer 8

The average of the values

Question 9

Explaining the meaning of:

s or σ

Answer 9

The average spread of the sample data around the mean

Question 10

Explaining the meaning of:

SE_x̄

Answer 10

How far from the sample mean the actual population mean is 68% likely to be

Question 11

Explaining the meaning of:

95% confidence

Answer 11

How far from the sample mean the actual population mean is 95% likely to be

Question 12

What does this image show?

Answer 12

Normal distribution

Question 13

Describe all important statistics in this image

Answer 13

Highest point = mean, median, and mode

s = standard deviation

Question 14

What percentage of samples are expected to fall in the red area?

Answer 14

50%

Question 15

What percentage of samples are expected to fall in the red area?

Answer 15

x̄ ± 1s = 68%

Question 16

What percentage of samples are expected to fall in the red area?

Answer 16

x̄ ± 2s = 95%

Question 17

Consider the following for a normally-distributed sample:

• x̄ = 10
• s = 3
• n = 100
• SE_x̄ = 0.3

What can you determine about the sample?

Answer 17

The mean sample value is 10.

68 individuals fell between 7 and 13

95 individuals fell between 4 and 17

Question 18

Consider the following for a normally-distributed sample:

• x̄ = 10
• s = 3
• n = 100
• SE_x̄ = 0.3

What can you determine about the population?

Answer 18

There is a 68% chance the population mean falls between 9.7 and 10.3

and a 95% chance the population mean falls between 9.4 and 10.6

Question 19

Compare

Sample and Population

Answer 19

Sample (n) is a subset of the population (N), and the goal is to have the sample be representative of the population

Question 20

What are the

Two Types of Data

Answer 20

Qualitative
and
Quantitative

Question 21

Types of

Quantitative Data

Answer 21

Raw data are directly measured / counted
Manipulated data are calculated based on raw data

Question 22

Examples of

Manipulated data

Answer 22

Mean, rates, and other statistical measures

Question 23

What should all tables contain?

Answer 23

1. Descriptive title that would allow the table to be understood even in absence of other information
2. Headers with units!
3. Data that has consistent decimal places and no units (already in the header)

Question 24

How to convert from base unit to milli
Ex: 5 liters → ? mL

Answer 24

Multiply by 1,000
i.e. Move decimal to the right three places
5 L = 5,000 mL

Question 25

How to convert from milli to micro
Ex: 5 mL → ? μL

Answer 25

Multiply by 1,000
i.e. Move decimal to the right three places
5 mL = 5,000 μL

Question 26

How to convert from base unit to micro
Ex: 5 liters → ? μL

Answer 26

Multiply by 1,000,000
i.e. Move decimal to the right six places
5 L = 5,000,000 μL

Question 27

How to convert from milli to base unit
Ex: 5 mL → ? L

Answer 27

Divide by 1,000
i.e. Move decimal to the left three places
5 mL = 0.005 L

Question 28

How to convert from micro to base unit
Ex: 5 μL → ? L

Answer 28

Divide by 1,000,000
i.e. Move decimal to the left six places
5 μL = 0. 000 005 L

Question 29

How to convert from micro to milli
Ex: 5 μL → ? mL

Answer 29

Divide by 1,000
i.e. Move decimal to the left three places
5 μL = 0.005 mL

Question 30

List

Three measures of Central Tendency

Answer 30

Mean (x̄) - average
Median - middle value
Mode - most common

Question 31

List

Two Measures of Variability

Answer 31

Range
Standard deviation (s or σ)

Question 32

What can increase confidence?

Remember: increasing confidence means lowering the confidence interval

Answer 32

Having a larger sample size
When the sample’s standard deviation is lower (note: this is just a characteristic of a set of data and cannot be affected by changing the sample size)

Question 33

Define

Rate

Answer 33

Manipulated data that divides two different units;
Usually some quantity / measurement divided by time

Question 34

In an equation, what is

Δ

Answer 34

Change in
Value after - value before

Δ is the capital Greek letter delta

Question 35

Importance of

Percent Change

Answer 35

Allows you to compare changes that occur when the starting values differ
Ex: A loss of $100 in a person that starts with $1,000 versus one that starts with $1,000,000; there is a higher percent change in the person that only started with $1,000

Question 36

How do you calculate percent change?

Answer 36