Unit one test

Question 1

define statistics

Answer 1

the science of collecting, organizing, summarizing, and analyzing information to draw conclusions or answer questions.

Question 2

what is a sample

Answer 2

a subset of the population that is being studied

Question 3

what is a parameter

Answer 3

a numerical summary of a population

Question 3

what is a population

Answer 3

the entire group of individuals to be studied

Question 3

what is an individual

Answer 3

a person or object that is a member of the population being studied

Question 4

what is qualitative data/variables & what does it measure

Answer 4

qualitative variables allow for classification of individuals based on some attribute or characteristic. Qualitative data are observations corresponding to a qualitative variable.

Question 4

what is a statistic

Answer 4

a numerical summary based on a sample

Question 5

what is the process of statistics

Answer 5

1. identify the research objective
2. collect data needed to answer the questions
3. describe the data
4. perform inference/ form conclusions

Question 6

what is a continuous variable

Answer 6

a quantitative variable that has an infinite amount of possible values

Question 6

what is quantitative data/variables & what does it measure

Answer 6

quantitative variables provide numerical measure of individuals. quantitative data are observations corresponding to quantitative variables

Question 7

what is a discrete variable

Answer 7

quantitative variable that has a countable number of possible values

Question 8

define nominal measurement

Answer 8

a variable is at the nominal level if the values of the variable name, label, or categorize.

Question 8

define ordinal measurement

Answer 8

Has the properties of the nominal level and the naming scheme allows for the values of the variable to be arranged or ranked.

Question 9

define interval measurement

Answer 9

has the properties of the ordinal level of measurement and the differences in the values of the variable have meaning.
**A value of zero in the interval level of measurement does NOT mean the absence of the quantity.

Question 9

what is a case control study

Answer 9

require individuals to look back in time

Question 9

define ratio measurement

Answer 9

has the properties of the interval level of measurement and the ratios of the values of the variable have meaning.
**A value of zero in the ratio level of measurement DOES mean the absence of the quantity.

Question 9

define simple random sampling

Answer 9

if every possible sample of size n has an equally likely chance of occurring

Question 9

what is a cross-sectional study

Answer 9

collect info about individuals at a SPECIFIC point in time, or lover a short period of time

Question 10

define cluster sampling

Answer 10

obtained by selecting all individuals within a randomly selected collection or group of individuals

Question 11

what is the difference b/w an observational study and a designed experiment

Answer 11

an observational experiment, the researcher observes behavior without trying to influence the study. in a designed experiment, the researcher intentionally changed the value of the explanatory variable.

Question 12

define stratified sampling

Answer 12

obtained by separating the population into nonoverlapping groups called strata and then obtaining a simple random sample from each stratum

Question 12

what is a cohort study

Answer 12

first identifies a group of individuals to participate in the study (the cohort)
they are observed over a LONG period of time

Question 13

define systematic sampling

Answer 13

obtained by selecting every kth individual from the population

Question 13

what is/why shouldn’t we use convenience sampling

Answer 13

a convenience sample is one in which the individuals in the sample are easily obtained.
– any studied that use this generally have suspect results

Question 14

what is response bias

Answer 14

when the answers on a survey do not reflect the true feelings of the respondent.

Question 15

what is non-response bias

Answer 15

when individuals selected to be in the sample who do not respond to the survey have different opinions from those who do.

Question 16

how do you calculate relative frequency

Answer 16

take the frequency pf a category and divide it by the sum of all frequencies

Question 16

what is sampling bias

Answer 16

the technique used to obtain the individuals to be in the sample tends to favor one part of the population over another.

Question 17

what is under coverage

Answer 17

the proportion of one segment of the population is lower in a sample than it is in the population.

Question 18

why do bars touch in a histogram

Answer 18

each interval starts from where the other ends (1-2.5, 2.6-3)

Question 19

when do you use mean

Answer 19

Mean is best used for a data set with numbers that are close together.

Question 20

what are the types of distribution

Answer 20

frequency distribution, relative frequency distribution,

Question 21

when do you use median

Answer 21

for skewed distributions or distributions with outliers

Question 21

when do you use mode

Answer 21

to summarize categorical variables

Question 22

what is range

Answer 22

The range generally gives you a good indicator of variability when you have a distribution without extreme values

Question 22

what is sample z score (formula and usage)

Question 23

what is population variance

Answer 23

a measure of dispersion that determines how far each data point is from the population mean.

Question 23

what is sample variance

Answer 23

the type of variance that is calculated using the sample data and measures the spread of data around the mean