Exam 1

Question 1

What are the 4 methods of establishing truth?

Answer 1

Authority, Rationalism, Intuition, and Scientific Method

Question 2

Authority

Answer 2

accepting information because it is from a highly respected source

Question 3

Rationalism

Answer 3

acquisition of knowledge through reason or logic

Question 4

Intuition

Answer 4

common-sense approach to acquiring knowledge; not based on reason

Question 5

Scientific Method

Answer 5

relies on objective assessment

Question 6

Observation vs Experimental

Answer 6

Observation does not influence any variable while experimental influences variables

Question 7

Descriptive vs Inferential Statistics

Answer 7

Descriptive describes the data while inferential is used to make inferences (generalization)

Question 8

Population

Answer 8

All the individuals of interest in a study

Question 9

Sample

Answer 9

A set of individuals selected from a population

Question 10

Variable

Answer 10

something that changes or has different values for different individuals

Question 11

Independent Variable

Answer 11

is the variable that is manipulated

Question 12

Dependent Variable

Answer 12

variable that is observed to asses the effect

Question 13

Constant

Answer 13

value does not change; control

Question 14

Data

Answer 14

measurement of observation of a variable

Question 15

Statistic

Answer 15

a value that describes a sample

Question 16

Parameter

Answer 16

value that describes a population

Question 17

Why is random sampling important?

Answer 17

It allows the data to be representative of the population

Question 18

What are the four measurement scales?

Answer 18

Nominal, Ordinal, Interval, and Ratio

Question 19

Nominal

Answer 19

label and categorize, NO NUMBERS; think of brands

Question 20

Ordinal

Answer 20

categorizes observations by ORDER; think of 1st place

Question 21

Interval

Answer 21

ordered categories, interval between categories of equal size; NO ZERO POINT (think of temperature)

Question 22

Ratio

Answer 22

same as interval but HAS A ZERO POINT (absolute zero); think of height

Question 23

Discrete Variable

Answer 23

whole countable numbers
Ex: 1, 2, 3, 4…

Question 24

Continuous Variable

Answer 24

infinite numbers possible
Ex: 1, 1.25, 1.26, 2, 2.34…

Question 25

Real limits

Answer 25

upper limit: will be .5 above the highest number
lower limit: .5 below the lowest number
EX: interval is 1-5 -> real limit is .5-5.5

Question 26

Rounding Numbers

Answer 26

below .5 = keep the same
above .5 = round up
equal to .5 (even) = stays the same
equal to .5 (odd) = round to next even number

Question 27

Frequency Distribution, why is it useful?

Answer 27

Present score values and their frequency of occurrence
shows the entire data

Question 28

Ungrouped vs. Grouped Frequency Distribution

Answer 28

ungrouped: raw scores can be pulled out, can find individual score
grouped: raw scores cannot be pulled out, no individual score, information is lost

Question 29

how to find the interval

Answer 29

i = range/ # of class interval
* class intervals are given*

Question 30

Relative Frequency (relative f)

Answer 30

proportion of total in interval
relative f = f/N
* should add up to 1*

Question 31

Cumulative Frequency

Answer 31

number of scores that fall bellow the upper real limit
* start at the bottom then add up
* final answer should equal to N

Question 32

Cumulative Percentage

Answer 32

Percentage of scores that fall below upper real limit of each interval
Cumulative % f= (f/N) x 100

Question 33

Percentile Point

Answer 33

% that falls bellow a specifice percentage (P30 = 30% of scores fall below this point)

Question 34

Percentile Point Formula

Answer 34

XsubL + (i/fsubi)(cumfsubp - cumfsubL)
XsubL = lower real limit of interval containing the percentile point
i = interval width
fsubi = freq. within the interval
cumfsubp = N x deciimal form of Psubx
cumfsubL = freq scores below the lower real limit (USE THE ROW BELOW)

Question 35

Percentile Rank

Answer 35

percentage of scores with values lower than the score in question
ex: 10% of scores fall below 59

Question 36

Percentile Rank Formula

Answer 36

(cumfsubL + (fsubi/i)(X-XsubL) / N) x 100

Question 37

Bar Graphs

Answer 37

best used for nominal or ordinal data
*bars do not touch

Question 38

Histogram

Answer 38

Best for interval or ratio data
* bars do touch each other

Question 39

Frequency Polygon

Answer 39

Used for interval or ratio data
* point is plotted over the midpoint of each interval

Question 40

Symmetrical vs Positive Skewed vs Negative Skewed

Answer 40

Symmetrical: normal curve
Positive: tail on the right
Negative: tail of the left

Question 41

Mean vs Median vs Mode

Answer 41

Mean: sum of all scores divided by total number
* is affected by outliers
Median: midpoint score
* not influenced by outliers
Mode: most common observation
* can be used for nominal data

Question 42

Overall Mean formula

Answer 42

M= sigmaX1 + sigmaX2 / n1 + n2
sigmaX1 = X-bar x n

Question 43

Mean and Median in Skewed Dist.

Answer 43

Positive = mean > median
Negative = mean < median

Question 44

Deviation Score

Answer 44

tells how far away the raw score is from the mean
sample: X - X-bar
Population: X - mu

Question 45

Sum of Squares (SS)

Answer 45

Raw Score method: sigmaXsqr - (sigmaX)sqr/N

Question 46

Variance calc. from SS

Answer 46

population: SS/N
sample: SS/N-1

Question 47

Standard Deviation calc. from SS

Answer 47

Population: sqrt SS/N or sqrt variance
Sample: sqrt SS/n-1 or sqrt variance

Question 48

Three measures of Variability

Answer 48

Range: max - min; overall spread
* is affected by extreme scores
Variance: average distance from the mean in squared units
Standard Deviation: average distance from the mean

Question 49

Z-Score

Answer 49

how many SD our score is from the mean