School

Ryerson UniversityDepartment

Quantitative MethodsCourse Code

QMS 102Professor

Jason ChanStudy Guide

FinalThis

**preview**shows half of the first page. to view the full**1 pages of the document.**•Descriptive statistics: methods of organizing, summarizing, and presenting data in an informative way.

•Inferential statistics: The methods used to find out something about population, based on a sample.

•Qualitative: Data containing descriptive information in words or numbers (numbers represent codes for associated words) Examples: Gender, staff

friendliness rating, customer satisfaction

•Quantitative: Data containing numerical information. Examples: monthly service charge, minimum balance to avoid fee, purchase amount

○Discrete: Numerical responses that arise from the counting process Examples: the number of bedrooms in a house, the number of customers

○Continuous: Numerical responses that arise froma measuring process. Take any value within an interval. Examples: purchase amount

•Nominal: no particular order or ranking, eg gender, world oil supply by country

•Ordinal: arranged in some order, the differences between data values cannot be determined or are meaningless, eg how the custom rates a store in a number

of areas (cleanliness, friendliness of staff) from 1-4

•Interval: there are units of measurement, data must be numeric, the value zero is only an arbitrary reference (does not mean there is no amount of the

characteristic), eg temperature on the Celsius scale

•Ratio: The zero point means absence of the characteristic (nothing), differences and ratios are meaningful, eg monthly income of surgeons, distance

traveled

•Stem and leaf plots: should be from 6 to 13 stems, numbers may be repeated twice or 5 times, unit must be indicated if stem not taken at face value, leaf for

each data value is the next single digit for the stem, 0-4, 5-9 or 0-1, 2-3, 4-5, 6-7, 8-9, no rounding off, no commas or dashes

+ are quartiles, line across is median, 0 is an outlier (falls between the fence), * Extremes are beyond the outer fence

IQRQRIF

×+=

5.1

3

IQRLIFLOF

×−=

5.1

IQRRIFROF

×+=

5.1

IQRQLIF

×−=

5.1

1

mean = median, symmetric, or zero skewness

mean < median, negative or left-skewed

mean > median, positive or right skewed

The Empirical Rule( Bell-shaped Distribution)

Approximately 68% of the values are within

σµ

±

Approximately 95% of the values are within

σµ

2

±

Approximately 99.7% of the values are within

σµ

3

±

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