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Flashcards in Statistics Deck (16)
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1

Mean

The sum of the items divided by the number of items.

2

How to calculate the mean for a frequency distribution?

1- Multiply each data value by its frequency
2- Find the sum of those products
3- Divide that answer by the total frequency of the distribution

3

Median

The data item in the exact middle number.
Or the mean of the two middlemost items.

4

Mode

The value that occurs most Frequently in a data set.
If more than one data value has the highest frequency then each of these data values is a mode.

5

Midrange

Lowest data value plus the highest data value divided by two

6

Range

Highest data value minus the lowest data value

7

Frequency distribution

Table with two columns
column one has data values
Column two has the frequency that data occurs

8

Inferential statistics

Making generalizations about drawing conclusions from data

9

Descriptive statistics

Concerned with collecting, organizing, summarizing, and presenting data

10

Measures of disbursement

Used to describe the spread of data items in a data set

11

Percentiles

Example: if I score is in the 45th percentile this means that 45% of the scores were less than that score

12

Z-score

Describes how many standard deviation’s a particular data item lives above or below the mean. The formula to find the Z score equals the data item minus the mean divided by standard deviation.

13

Normal distribution
AKA Gaussian distribution

On a graph it would appear to be a bell curve. The mean, median and mode are all equal and located at the center.

14

Standard deviation

Found by determining how much each data item differs from the mean.
A complicated formula involving square root.

15

Random sample

A sample obtained in such a way that every element in the population has an equal chance of being selected for the sample

16

Quartiles

Data sets divided into four equal parts.
First quartile: up to 25th percentile
Second quartile: 50th percentile
Third quartile: 75th percentile