Chapter 1

Question 1

Statistics

Answer 1

The study of methods to describe and measure aspects of nature from samples.

Question 2

Statistical Hypothesis Testing

Answer 2

Specific claim about a population parameter

Question 3

Population

Answer 3

All of the individuals in the world

Question 4

Samples

Answer 4

A subset of the population of interest
- Can be individual or group of individuals

Question 5

Parameter

Answer 5

A quantity describing a population (measurement or observation)

Question 6

Estimate

Answer 6

A quantity calculated from a sample

Question 7

Sampling Bias

Answer 7

A systematic difference between parameter and its estimate
- Occurs when the samples aren’t representative of the population

Question 8

Sampling Error

Answer 8

Undirected deviation of estimates away from parameters

Question 9

Volunteer Bias

Answer 9

Volunteers are likely to be different on average from the population

Question 10

Properties of Good Sample

Answer 10

Random and Independent (Equal chance of selection) selection

Question 11

Variable

Answer 11

Any characteristics or measurements that differs from individual to individual

Question 12

Data

Answer 12

Measurement of the variables

Question 13

What ate the two types of variable?

Answer 13

Numeric (Quantitative) and categorical (Qualitative)

Question 14

Numeric Variable

Answer 14

Magnitude on a numeric scale

Question 15

Categorical Variable

Answer 15

Describe members in a category or groups
1. Ordinal: can be ranked (sizes)
2. Nominal: cannot be ranked (sex chromosomes)

Question 16

Numerical Data

Answer 16

Continuous - continued with decimals or fractions
Discrete - whole number, can be counted

Question 17

Explanatory Variable

Answer 17

Manipulated by the researcher: “Independent”

Question 18

Response Variable

Answer 18

Measured effect: “Dependent”

Question 19

Frequency Distribution

Answer 19

Shows how often each value of the variable occurs in the sample: common values, rare values, average, and variation.

Question 20

What are the two types of Probability distribution?

Answer 20

Actual and Theoretical (normal distribution)

Question 21

Actual/Real distribution is almost never known…Why not?

Answer 21

For actual, needs to measure every member of the population!

Question 22

Experimental Studies

Answer 22

Researchers assign treatments to individuals
1. Controlling a variable (placebo/non placebo)
2. Cause and effect

Question 23

Observation Studies

Answer 23

Researches do not assign treatments
1. Observe association

Question 24

Observation studies CANNOT

Answer 24

Prove causation or disentangle cause and effect

Question 25

Why bother with observation studies?

Answer 25

Gather information to plan an experiments and ethics cannot do experiments such as on pregnant women and smoking

Question 26

Confounding Variables

Answer 26

Variable that are not considered in an experimental study but they may affect the response variable

Question 27

How could experimental studies remove confounding?

Answer 27

Through random assignment of treatment

Question 28

Examples: “The number of violent crimes tend to increase when ice-cream sales increase”
What is the confounding variable?

Answer 28

Heat

Question 29

Well designed experiment can reveal causation. What could be considered as a well designed experiment?

Answer 29

Random assignments and artifacts (placebo effects)