Data Handling And Analysis

Question 1

What are the measures of central tendency and dispersion

Answer 1

Mean, median, mode, range and standard deviation

Question 2

Discuss and evaluate mean

Answer 2

Add up all numbers and divide by N ratio and interval data only
Most sensitive because uses exact distance, distorted by extreme values, but not appropriate for ordinal data or discrete values

Question 3

Discuss and evaluate the median

Answer 3

Are you unselect midpoint the ratio, interval and ordinal data
Useful for extreme values, but not as sensitive as mean

Question 4

Discuss and evaluate the mode

Answer 4

Most common value or group. Maybe bimodal. Can be used with all levels of measurement
Useful for nominal data, but not good when there are many modal groups

Question 5

Discuss and evaluate the range

Answer 5

Subtract lowest from highest and add the correction of one

Easy to calculate, but affected by extreme numbers and doesn’t reflect the data distribution

Question 6

Discuss and evaluate standard deviation

Answer 6

Average distance between each number and the main

Takes exact values into account may be affected by extreme values

Question 7

How do you display quantitive data

Answer 7

Tables and graphs must have a title and clear labels
Tables may contain measures of central tendency and dispersion
Bar chart, histogram, line graph, scattergram

Question 8

Explain a bar chart

Answer 8

Height of bar represents frequency, date on X axis may not be continuous

Question 9

Explain the histogram

Answer 9

Represents frequency of continuous data, true zero and bobs next to each other

Question 10

Explain a line graph

Answer 10

Frequency represented by a line rather than bars

Question 11

Explain a scattergram

Answer 11

Shows correlation between covariables

Question 12

What are the types of data distributions

Answer 12

Normal distribution, positive skew, negative skew

Question 13

Discuss a normal distribution

Answer 13

Symmetrical bell shaped curve; mean, median and mode at midpoint; about 68% of people are one standard deviation above and below the midpoint, 95% within two standard deviation from midpoint

Question 14

Discuss a positive skew

Answer 14

Tail to right, occurs eg: test too hard

Question 15

Discuss a negative skew

Answer 15

Tail to left, because e.g. when test to easy

Question 16

What are the types of data

Answer 16

Quantitive
Qualitative
Primary
Secondary

Question 17

Discuss and evaluate quantitive data

Answer 17

Numerical, easy to analyse but may not represent reality

Question 18

Discuss and evaluate quantitative data

Answer 18

Can’t be directly counted, detailed and possibly unexpected information, but more difficult to draw conclusions

Question 19

Discuss and evaluate primary data

Answer 19

Collected by the researcher for current study, involves design a study to collect data. Suits the needs of the study, but time-consuming and expensive

Question 20

Discuss and evaluate secondary data

Answer 20

Using data collected for previous study. Saves time and money but may not fit exact needs of study

Question 21

When do you use the sign test

Answer 21

With paired or related data

Question 22

How do you do the sign test

Answer 22

Represent each pair of data with plus or minus, calculated value of S= less frequent sign
Look up critical value of S, need to know N and whether one-tailed or two-tailed test
Conclusion is if the calculation value is less than or equal to critical value the difference is significant
Probability level of 5% is commonly used