Quiz 1/Midterm 1

Question 1

What are statistics?

Answer 1

Rules and mathematical procedures used to present results of investigations

Question 2

What are the two broad classes of statistic?

Answer 2

Descriptive statistics and inferential statistics

Question 3

What are descriptive statistics?

Answer 3

Describe observations/relationships (e.g. mean, range). Straight forward. Based on a sample.

Question 4

What are inferential statistics?

Answer 4

They take observations and make conclusions beyond people you observe. They make generalizations about a population. Involves probability.

Question 5

What is the scientific method?

Answer 5

A way of finding things out about the world. It is a combination of objective observation (descriptive stats) and reasoning/logic.

Question 6

What is inductive logic?

Answer 6

Inductive logic goes from a specific premise, and makes a generalization to a general conclusion. Ex. My cat has fleas so all cats have fleas. Uses inferential stats.

Question 7

What is deductive logic?

Answer 7

Goes from a general premise to specific conclusion, not using statistics. All cats have fleas, therefore my cat has fleas.

Question 8

What is a variable?

Answer 8

An attribute/property/condition being observed.

Question 9

What are the goals of the scientific method?

Answer 9

1 - Objectively observe and describe lawful relationships b/n variables (descriptive stats)
2 - Predict new observations/generalize using inductive logic.
3 - Explain why observed relationship occurs (Theory)

Question 10

What is a constant?

Answer 10

An attribute that only takes on one value (ex. room full of people with same hair colour).

Question 11

How many variables must be involved in a relationship?

Answer 11

2

Question 12

What is sampling error?

Answer 12

The sample may not be representative of the population. A larger sample = less chance of error.

Question 13

What is the difference b/n theory and an observation?

Answer 13

Theory gives a REASON for association

Question 14

How do you test a theory?

Answer 14

Theory > Operational Definition > IV and DV > Experimental Hypothesis > Sample > Random Assignment > Make observations > Descriptive Stats > Inferential Stats > Leap back to theory

Question 15

What is an operational definition?

Answer 15

Defines variables in terms of operation you use to measure it.

Question 16

What is an experimental hypothesis?

Answer 16

Explaining what you expect to happen (NOT why)

Question 17

What is a random sample?

Answer 17

Sample randomly chose from entire population (rare)

Question 18

What is a convenience sample?

Answer 18

Uses sample that is available (ex. uni students)

Question 19

What can bring about error in the scientific method?

Answer 19

Problems in operational definition (not measuring what is intended, confounds (extraneous/nuisance variables), and sampling error (atypical sample)

Question 20

Why are the type of study/scale important?

Answer 20

Helps determine what type of statistical analysis, determines proper way to graph, and determines strength of conclusions.

Question 21

What is a manipulated variable?

Answer 21

Experimentor controls, makes it one way, determines condition

Question 22

What is a measured variable?

Answer 22

Observe and if possible, quantify/categorize

Question 23

What is the nominal scale of measurement?

Answer 23

Simplest - categories. Qualitative.

Question 24

What is the ordinal scale of measurement?

Answer 24

Ranking (e.g. 1st, 2nd, 3rd). Distances b/n intervals may not be equal. Can’t do averages.

Question 25

What is the interval scale of measurement?

Answer 25

Rating scales, personality tests. Quantitative. Equal intervals. Can use averages.

Question 26

What is the ratio scale of measurement?

Answer 26

Quantitative. Equal size intervals. True zero point. Can use '2x'.

Question 27

What is a true experiment?

Answer 27

All IV are manipulated. Random assignment. DV measured. Testing a theory. Use a bar or line graph.

Question 28

What is a correlational study?

Answer 28

Least control. All variables are measured - no manipulations, No IV or DV. Use correlation coefficient 'r'. Use a scatter plot to show an association. One variable does not necessarily cause another.

Question 29

What is a quasi-experiment?

Answer 29

One or more non-manipulated IV. Divide participants into groups based on previously existing conditions. Only measured variables.

Question 30

What is the difference b/n real and apparent limits?

Answer 30

Real limits are in between intervals (eg 8.5-9.5), and apparent limits are values of scores that are highest and lowest in an interval (eg 9)

Question 31

When are grouped frequency distributions used?

Answer 31

When you have a wide range in variable you are measuring.

Question 32

What are grouped frequency distributions?

Answer 32

Frequency distributions made up of an ordered list of class intervals.

Question 33

What is a class interval?

Answer 33

Lower limit - Upper limit

Question 34

What are the rules for a professional looking frequency distribution?

Answer 34

1 - 5-15 Class intervals 2 - Convenient counting interval size 3 - All intervals equal size 4 - Lower limits have to be even multiples of chosen interval size

Question 35

How do you make a frequency distribution?

Answer 35

1 - Calculate # of rows (Range+1) 2 - Divide by 10 to get interval size 3 - Choose convenient counting interval 4 - Make lowest apparent limit = multiple of interval size.

Question 36

How many decimals of accuracy do we need?

Answer 36

2

Question 37

What does a normal distribution look like?

Answer 37

Bell curve, symmetrical

Question 38

What does a positive skew look like?

Answer 38

Tail to the right. Average is higher than most scores.

Question 39

What does a negative skew look like?

Answer 39

Tail to the left. Average is lower than most scores.

Question 40

What does central tendency tell you?

Answer 40

The typical score.

Question 41

What is the mode?

Answer 41

Most common score. Can be no mode or more than one. Can also be used with nominal data.

Question 42

What is variability?

Answer 42

Individual differences within the data. Variability determines whether measures of central tendency are accurate.

Question 43

What are some measures of variability?

Answer 43

Range, standard deviation

Question 44

What is the standard deviation?

Answer 44

Typical distance between each score and the mean. (Population /n, and sample /(n-1) )

Question 45

What is the definitional formula for SS?

Answer 45

SS = Sum(X-M)^2

Question 46

What is the variance?

Answer 46

SD^2. The squared typical distance between each point and the mean.

Question 47

What are statistics?

Answer 47

Set of mathematical procedures for organizing, summarizing and interpreting information

Question 48

What is a parameter?

Answer 48

Value of numbers that describes a population

Question 49

What is a nonequivalent groups study?

Answer 49

Research in which collections of participants are formed without the researcher controlling assignment

Question 50

What is a pre-post study?

Answer 50

Evaluation of a treatment's effect by comparing observations before and after the treatment

Question 51

What does biased mean?

Answer 51

Description of a statistic for which the average value is unequal to the parameter

Question 52

What does unbiased mean?

Answer 52

Description of a statistic for which the average value is equal to the population parameter

Question 53

What is a biased statistic?

Answer 53

Metric that consistently tends to over/underestimate the population parameter

Question 54

What is an unbiased statistic?

Answer 54

Metric that provides an accurate estimate of the corresponding population parameter