Stats I

Question 1

What are the two major statistical methods?

Answer 1

Descriptive stats

Inferential stats

Question 2

What is descriptive statistics?

Answer 2

Describe collected data

Question 3

What are inferential statistics?

Answer 3

Estimation and hypothesis testing to make decisions about populations

Question 4

What are experimental units?

Answer 4

Object upon which we collect data (people, schools, hospitals etc)

Question 5

What is a population?

Answer 5

All items of interest

Question 6

What are variables?

Answer 6

Characteristics of individual experiemental units

Question 7

What is a sample?

Answer 7

Subset of the units of a population

Question 8

What are parameters?

Answer 8

numbers that summarize data for an entire population

Question 9

What is a statistic?

Answer 9

numbers that summarize data from a sample, i.e. some subset of the entire population

Question 10

Samples come from what?

Answer 10

Population or a process

Question 11

What are the two categories of variables?

Answer 11

Categorical

Quantitative

Question 12

What is a categorical variable?

Answer 12

The presence of absence of something

The relative weight or rank of the thing that is of research interest

Question 13

What is a process?

Answer 13

A series of actions or operations that transforms inputs to outputs

Question 14

What is the nominal scale?

Answer 14

Categories without order

Question 15

What are ordinal scales?

Answer 15

Nominal variables with an inherent order among the categories

Question 16

What are interval scales?

Answer 16

Measurable difference or interval or distance between observations

Question 17

What is a ratio?

Answer 17

Same as interval, but with an absolute reference point

Question 18

How is qualitative data presented?

Answer 18

Bar graphs

Pie charts

Question 19

How is quantitative data presented?

Answer 19

Dot plot
Stem & leaf plot
Frequency distribution

Question 20

What is a summary table?

Answer 20

Lists categories and number of elements in a category

Question 21

What is a class?

Answer 21

One categories into which qualitative data can be classified

Question 22

What is class frequency?

Answer 22

The number of observations in the date set falling into a particualr class

Question 23

What is the class relative frequency?

Answer 23

the class frequency, divided by the total numbers of observations in the data set

Question 24

What is a class percentage?

Answer 24

the class relative frequency, multiplied by 100

Question 25

What is a stem and leaf plot?

Answer 25

Tens place on the left hand side of a bar, with ones place of data on the right.

Question 26

What is a histogram?

Answer 26

bar graph of non-categorical values

Question 27

What is a dot plot?

Answer 27

Dots on a horizontal scale (Y axis being frequency)

Question 28

What is a central tendency?

Answer 28

tendency of the data to cluster or center about certain numerical values

Question 29

What is variability?

Answer 29

Spread of the data

Question 30

n is notation for what? How about N?

Answer 30

``` n = sample N = population ```

Question 31

Sample mean has what notation?

Answer 31

X bar

Question 32

Population mean has what notation?

Answer 32

μ

Question 33

Why is the mean not always the best measure of central tendency?

Answer 33

Affected by extreme values

Question 34

What happens to the median if there is an even number of values?

Answer 34

average of two central points

Question 35

What is the value of the median?

Answer 35

Not affected by extreme values

Question 36

What is the only measure of central tendency that can be used on qualitative variables?

Answer 36

Mode

Question 37

What is the range?

Answer 37

Measure of dispersion | difference between the highest and lowest values in a given set of values

Question 38

What is the notation for standard deviation for a sample? Population?

Answer 38

s for sample | Sigma for population

Question 39

Variance is what?

Answer 39

s^2 | Sigma ^2

Question 40

Why do you subtract 1 from n in the denominator for variance calculations of samples?

Answer 40

Degree of freedom

Question 41

What does it mean for a bell curve to be symmetric?

Answer 41

Mean=median

Question 42

if mean

Answer 42

Left skewed

Question 43

if mean > median, then the bell curve is curved left or right?

Answer 43

Right skewed

Question 44

1 standard deviation accounts for what percent (in a normal distribution)?

Answer 44

68%

Question 45

2 standard deviations account for what percent (in a normal distribution)?

Answer 45

95%

Question 46

3 standard deviations account for what percent (in a normal distribution)?

Answer 46

99.7%

Question 47

Which scale: simplest level of measurement--categories without order (qualitative)

Answer 47

Nominal scale

Question 48

Which scale: Nominal variables with an inherent order among the categories (qualitative)

Answer 48

Ordinal

Question 49

Which scale: Measureable difference or interval or distance between observations

Answer 49

Interval scale

Question 50

Which scale: measureable or interval distance between observations, with an absolute reference point (such as 0)

Answer 50

Ratio