descriptive statistics

what are descriptive statistics?

they describe the data and show a summary of the results

what are examples of descriptive statistics?

measures of central tendency (mode, mean, median) and measures of dispersion (range, variance)

what are measures of central tendency?

mode, median and mean

what is the mean?

the average

how do you calculate the mean?

you add the value of each number and divide it by how many numbers there are.

what is a strength of calculating the mean?

it is an accurate average as it takes all the data into account

what is a weakness of calculating a mean?

it can be influenced by anomalies.

what is the mode?

the number that occurs the most often

what is a strength of calculating the mode?

it is unaffected by anomalies

what is a weakness of calculating the mode?

it doesn’t take all the scores of the data into consideration

how do you calculate the mode?

order the numbers lowest to highest and see which number appears the most often.

what is the median?

calculated by finding the middle score when the data set is placed in numerical order.

what is a strength of calculating the median?

it is unaffected by anomalies. Making it more representative of the whole data set.

what is a weakness of calculating the median?

it doesn’t take all the scores in the data set into consideration as it is only concerned with the middle number. Ignoring all other data, means it may not accurately measure central tendency.

how do you cancel median?

calculated by finding the middle score when the data set is placed in numerical order. If there is an even number of data, then the median is the sum of the two middle numbers, divided by two.

what are measures of dispersion?

describe the spread of data around a central value (mean, median or mode). They tell us how much variability there is in the data. There are two measures of dispersion: range and standard deviation (SD) 

what is the range?

the difference between your highest and lowest values

what is a strength of calculating the range?

easy to calculate mathematically without using a calculator.

what is a weakness of calculating the range?

it does not indicate the distribution pattern across the whole data set.

how do you calculate the range?

smallest value subtracted from the largest value

what is standard deviation?

a measure which shows to what extent the values in a set of data deviate from the mean.

how do you calculate a percentage?

(value/total value)x100