Stats Unit 1 Test Vocab and Review

Front Range Community College MAT 1260 Unit 1 Review

Types of variables

Discrete or continuous

Discrete definition

an exact value will occur

Continuous definition

Any possible value can occur

Types of data

Qualitative or quantitative

Types of sampling (RSS, CCC)

Simple Random (SRS), Systematic, Stratified, Cluster, Convenience, Census

Simple random sampling definition

a certain number of individuals are randomly selected

systematic sampling definition

every Xth person in a sample, X is the frame

stratified sampling definition

sample taken from like-minded groups (like Freshmen, Sophomores, Juniors, Seniors)

cluster sample definition

population is randomly split into clusters of individuals and each cluster is randomly selected

convenience sampling definition

individual reported information and is very sketchy

census sampling definition

every person in the population

how do you find the ideal class width

range/classes

range = max-min

classes = between 5 and 20 up to you

What’s the first step of creating a frequency table?

create your class width

if mean > [is greater than] median, then the graph is skewed…

right

if mean < [is less than] median, then the graph is skewed…

left

if a graph is skewed right, describe mean, median and mode

mode < [is less than] median < [is less than] mean

if a graph is skewed left, describe mean, median and mode

mean < [is less than] median < [is less than] mode

if the graph is skewed at all, what measure of center is best?

median

what is the measure of central tendency?

a numerical summary of the data in the middle

what is the measure of dispersion?

how spread out the data points are

do you use absolute value in z scores?

naur

what is the raw score formula?

x=(z*stdev)+mean

if comparing two independent events relatively, what do you use?

z score

5 point summary values

minimum, Q1, median, Q3, maximum

when “order matters,” does that include ordered pairs of doubles?

nope- you don’t need to write (1a,1b) and (1b,1a). the order matters part just means (1,2) and (2,1) are different.

types of probability (ETSS)

empirical, theoretical (classical), subjective, simulation

empirical probability definition

observation of actual outcomes

ex: i roll one dice 6 times and get {2,2,3,4,1,5}. therefore, the odds of rolling a 2 is 2/6.

theoretical (classical) probability definition

favorable number of outcomes over the total possible number of outcomes

“in an ideal world”

ex: a dice has 6 sides, so the odds of rolling a 5 is 1/6.

subjective probability definition

not based on data values but a judgement, intuition, or belief

ex: 85% chance of rain tomorrow

simulation probability definition

the actual situation is simulated for similar to real life results

ex: seat belt testing done on dummies to say “my seatbelts are 99% effective”

what does the symbol V mean?

or

what does the symbol ^ mean?

and

what does the symbol x̄ mean?

sample mean (x bar)

what does the symbol μ mean?

population mean (mew)

what does the symbol σ mean?

population standard deviation (sigma)

what does the symbol s mean?

sample standard deviation (lowercase s)

how do you find standard deviation by hand?

1. identify the score

2. identify the sample or population mean

3. identify the deviation about the mean for each score

4. square the deviation about the mean

5. add up the squared values

6. divide the added up values by the number of values in total (for a population, use number of values total. for sample, use number of values minus 1)

7. square root the divided number

8. simplify

difference in standard deviation for population and samples

population stdev: divide by number of values (n)

sample stdev: divide by number of values minus 1 (n-1)

what is variance?

the value of stdev before it is squared