Descriptive Statsics And Measures Of Central Tedacy

Question 1

What are Descriptive statistics used for?

Answer 1

-to describe/summarise the charterstics of a sample or data set.(standard deviation,frequency)

Question 2

What are some examples of the measures of central tendency?

Answer 2

-mean
-median
-mode
MOCT-inform us about central values for a set of data

Question 3

What are some examples of measures of dispersion?

Answer 3

-Range
-Standard deviation

Question 4

Define the mode

Answer 4

The most frequently occurring value in a set of scores

Question 5

Describe how the mean is caculated?

Answer 5

-adding up all the data items in a data set and dividing by the total number of items.

Question 6

What are 3 strengths of using the mean?

Answer 6

-Most sensitive measure of central tendency-takes into account the exact distance between all values of the data.
-necessary for further statistical analysis
-always be found using ordinary/abouve level data.

Question 7

What are 3 weaknesses of using the mean?

Answer 7

-Senstivity means it can be easily distorted by one of the extreme values-less represprintive of data as a whole.
-Can’t be used with norminal data
-may produce a non sense value not in the original data

Question 8

Describe how to calculate the median?

Answer 8

-Middle value in an ordered list
-All data items must be arranged in the order and central value is the median.

Question 9

What are 3 strengths of using the median?

Answer 9

-Not affected by extreme scores so can be useful under cirmustances
-appropriate for ordinal and abouve data
-easier to calculate than mean-doesn’t require a calculation

Question 10

3 weaknessses of using the median?

Answer 10

-Not useful for further stastical analysis
-May produce a non sense value that was not used in the organically data set.

Question 11

How to calculate the mode?

Answer 11

-Value that is most common data item with norminal data is the category that has the highest frequency count.
-Modal group is the group with the greatest frequency.
-if 2 categories have the same frequency category-the data has 2 modes.

NOTE-WITH INTERVAL AND ORDINAL DATA-ITEM THAT OCCURS MOST FREQUENTLY

Question 12

What are strengths of using the mode?

Answer 12

-Value will be in the data set
-most useful when the data is in categories

Question 13

2 weaknesses of using the mode?

Answer 13

-not useful for describing data when there are several modes
-not useful is the distribution is skewed-it may not display what is occurring in the centre of the data

Question 14

Appropriate measures of central tendency-what is the most approximate measure of central tendancy to use for norminal data?

Answer 14

Mode

Question 15

What are the 2 most appropriate measures of central tendancy to use for ordinal data?

Answer 15

-Mode
-Median

Question 16

What are the 3 most appropriate measures of central tendancy to use for interval and ratio data?

Answer 16

-Mode
-Median
-Mean

Question 17

Define the median

Answer 17

The mid point in a set of data that has been placed in order.

Question 18

Define what is meant by measures of central tendancy?

Answer 18

A form of estimation of a mid point/average in a set of data

Question 19

Define the mean

Answer 19

The average that is shown by all scores in the data set when they are divided by N

Question 20

Define the mode

Answer 20

The most common value within a set of data

Question 21

Define measures of dispersion?

Answer 21

A measure that shows the spread of data whether it is tightly clustered or has a broader spread

Question 22

Define range

Answer 22

A value which shows the spread of data representing the differences between scores

Question 23

Define standard deviation

Answer 23

A value which represents the amount of variation of results from the mean score

Question 24

Give 2 strengths of the range

Answer 24

-Indicates the consistency of the data

-Relativley easy to calculate in comparison of standard deviation-because the range involves 1 step which is the highest value take the lowest whereas standard deviation involves multiple steps.

Question 25

Give 2 weaknesses of the range

Answer 25

-It is affected by extreme values because the values at the highest and lowest end of the set are used-may not actually reflect the data set accurately. -Fails to take into account the distribution of numbers-doesn’t indicate whether most numbers are closely grouped or spread around the mean

Question 26

What the 6 steps to calculate standard deviation?

Answer 26

-1-work out the mean set of data 2-Substarct the mean from each data point 3-Square the results 4- Add these results up 5-Divide by n-1 6-Caculate the square root

Question 27

What is 2 strengths of using standard deviation?

Answer 27

-It is a precise measure of dispersion -we know whether values are closely grouped or spread around the mean -It is not affected by extreme values because it does not just look at the highest and lowest value data set-increasing validity

Question 28

What are 2 weaknesses of using standard deviation?

Answer 28

-It may hide characteristics of data like extreme values because it indicates how far each value is from the mean rather than looking at values at the end of each data set -