Basic Statistics

Scales of measurement Nominal

The one that has names Ordinal

Rank ordered Interval

Equal differences in the scores Ratio

Has a true 0

Measures of Central Tendency Mode

The most frequent number The bump in the graph

Measures of Central Tendency Median

The one in the middle Is a number in the array except in case of ties

Measures of Central Tendency Mean

Arithmetic average The total of the numbers divided by the number

of cases

Frequency Distribution A method of examining a group of scores

Ted 100 Amy 80 Carmen 85 Carol 85 Ralph 75 Tony 85 Juanna 98 Martin 100 Celeste 98 Mo 100 Joaquinne 95

Tally Score

75 1 1 80 1 1 85 111 3 95 1 1 98 11 2 100 111 3

Variance

How are the score spread out

Tells more than the mean of the group

Variance How are the scores spread out?

In other words, how far do the scores range from the mean?

Scores: 10, 12, 13, 10, 9, 2, 13, 12, 12, 10

Measures of Central tendency101213109213121210

Sum = 103

Mean= 10.3

Median= 11

Mode = 10 and 12

Variance101213102913121210

-0.31.72.7-0.3-8.3-1.32.71.71.7-0.3

.092.897.29.0968.891.697.292.892.89.09

sum of squares = 94.1

91.4/10 = 9.14

Square root of variance = 3.02