Statistics

Statistics

A discipline concerned with (1) the organization and summarization of data and (2) the drawing of references about the characteristics of some collection of persons or things when only a portion of these characteristics are available for study

Biostatistics

the branch of statistics that deals primarily with the biological sciences and medical/health-related disciplines

Population

A set of persons or objects that have a common observable characteristic. Sometimes can be referred to the data and not to people

Example -population- students at Claflin university

Sample

a subset, or part, of a population

Example senior class

Data

Recordings of measurements made on characteristics

Example blood pressure of students

Parameter

Any summarization of the elements of a population while a like summarization of the elements of a sample is referred to as a statistic

Statistic

A like summarization of the elements of a sample

Descriptive statistics

Made up of various techniques used to summarize the information contained in a data set. Deals with the description of data such as means, ranges, bar graphs, etc.

inferential statistics

Made up of various techniques used to provide information about parameter values based on observations made on the values of statistics. Deals with making inferences on a population based on observations.

Measure

To assign numbers, letters, words, or some other symbol to persons or things in order to convey information about the characteristic being measured

The nominal scale

-Based on a qualitative assessment of the characteristics

-the levels of measurement are not comparable based on the level. I.e. the levels are not gender than or less than another level.

Examples: gender, blood type, area codes, etc.

ordinal scale

Classifies persons or things by the characteristics being assessed, but the scale is ordered

The categories are ordered but you don't know how much more one level is to the other level

Examples) categories such as: none, mild, moderate, or severe

Common in health-related fields

The interval (or equal interval) scale

Ordered categories but how much more and how much less is expressed here

No true zero point

Example temperature

It can take on a negative value

ratio scale

Similar to the interval scale but includes a true zero point

Examples heights and weights

Brain volume (cm3)

continuous variable

Can take on any value in a specified range. Typically, the range is infinite and values can be decimals

Example weight

Discrete variable (countable)

Not continuous; can only take a discrete number of values. If values are limited to only two such as gender, then the variable is considered to be dichotomous

Male or female

True or false

Yes or no

Right or wrong

Number of children

Number of fatalities

bar graphs

Uses horizontal or vertical bars to classify data into categories by their frequency

Histogram

A graph that displays the data using vertical bars of various heights to represent the frequencies of the classes

Polygons

Similar to a line graph. The points or dots are placed in the same place like a histogram and then connected to make a line

Stem-and-leaf displays

Is a data plot that uses part of the data as the stem and part of the data value as the lead to form groups or classes

Skew

The degree of a asymmetry in a distribution. Data falling to one direction of a graph of the majority of the data falls into one side.

negatively skewed

When most of the data falls to the right of the mean

positively skewed

When most of the data falls to the left of the mean

symmetric

Data values are evenly distributed on both sides of the mean

Kurtosis

Peakedness of a distribution relative to the length and size of its tails

Kurtosis- leptokurtic

Sharp peaks

Kurtosis: Platykurtic

Flattened middles

Statistic or parameter : the average (mean) volume of brains included in data set 9 in appendix b is 1126.0 cm3

Statistic

Statistic or parameter: California survey includes 2799 adolescent residents of California

Statistic

Statistic or parameter: a data set includes measurements from 25 king-size cigarettes, and the average (mean) amount of nicotine in those 25 cigarettes is 1.26 mg

Statistic

Statistic or parameter: a deadly disaster in the United States was the triangle shirtwaist factory fire in New York City. A population of 146 garment workers died in that fire

Parameter

Statistic or parameter: in a study of 400 babies born at 4 different hospitals in New York State, it was found that the average (mean) weight at birth was 3152.0 grams

Statistic

Statistic or parameter: in the same study, 51% of the babies were girls

Statistic

Statistic or parameter: a study was conducted of all 2223 passengers aboard the titanic when it sank

Parameter

Statistic or parameter: the average (mean) atomic weight of all elements in the periodic table is 134.355 unified atomic mass units

parameter

Discrete or continuous: in a study of weight gains by college students in their freshman year, researchers record the amounts of weight gained by randomly selected students

Continuous

Discrete or continuous: data set 3 includes the length of stay (in days) for each baby in a sample of babies born in New York State. The first few values are 2, 2, 36, 5, and 2

Discrete

Discrete or continuous: among the subjects surveyed as part of the California health interview survey, several subjects are randomly selected and their heights are recorded

Continuous

Discrete or continuous: from data set 1 we see that a female had an arm circumference of 32.49 cm

Continuous

Discrete or continuous: a sample of married couples is randomly selected and the number of children in each family is recorded

Discrete

Discrete or continuous: when studying the relationship between lengths of feet and heights so that footprint evidence at a crime scene can be used to estimate the height of the suspect, a researcher records the exact lengths of feet from a large sample of random subjects

Continuous

Discrete or continuous: the emergency room of the Albany medical center records the numbers of stitches used for patients in a week

Discrete

Discrete or continuous: the insurance institute for highway safety collects data consisting of the numbers of motor vehicle fatalities caused by driving while texting

Discrete

which scale of measurement? Brain volume (cm3)

Ratio

Scale of measurement? Blood lead levels of low, medium, and high used to describe subjects

Ordinal

Body temperature

Interval

Privacy codes

Nominal

hospital

Nominal

Hospital charges

Ratio

Physician ranks

Ordinal

Record of years in which new products were launched, beginning with 1849

Nominal