stats 1

descriptive statistics

• describes or summerises characteristics of a data set

• eg mean mediam mode

inferential statistics

• uses sample data to makee inferences or conclusions about a population

• eg sampling

population

• refers to a set or collection of all possible observations of some specific characteristics

• survey that includes every element in the population is known as census

• parameter is a characteristics of the population

sample

• refers to a portion of the population

• survey that involves a sample is. known as a sample survey or sampling

• statistics is a measure characteristic of the sample

qualitative data

categorical responses

quantitative data

numerical responses

discrete

• can assume values only at specific points on a scale of values with gaps between them

• arises from counting

continuous

• can assume all values within an interval

• arises from measuring

element or member

specific subject or object about which the infomation is collected

variable

characteristics under study that assumes different vlaues for different elements

data point

value of an observation

data set

collection of data points

steps of surveys

1. objective of survey

2. target population

3. sampling method

4. survey method

5. design questionnaire

6. pilot survey

7. main survey

8. analyze data

9. present findings & make reccomendations

methods of survey

• personal interview

• mail questionnaire

• telephone surey

• direct observation

• published materials

personal interview

direct interaction between interviewer and interviewee

mail questionnaire

questionaires sent through the mail

telephone survey

conducted through telephone

direct observation

involves the observer to physically observe the participants whos unaware

published materials

reference to published results of surveys carried out by others

questionnaire design

• short (number of qns and length)

• simple to understand

• avoid personal and sensitive matters

• elicit data and information required

• orderly and systematically laid out

• clear instructions to complete the questionnaire

• avoid ambiguous question

• questions not to lear to certain answers