Statistics Quiz 2

Random

-Subjects are selected by random -Sampling method -Ex. number each subject in a population. Put in a bowl in draw randomly

Sampling Methods

1. Random 2. Systematic 3. Stratified 4. Cluster

The amount of money a person earns per week working at a fast-food restaurant A. Discrete B. Continuous

A. Discrete

Experimental Study

The researcher manipulates one of the variables and tries to determine how the manipulation influences other variables

Nominal Level Example

-Zipcode -Gender (male, female) Eye color (blue, brown, green hazel) -Political affiliation, Religious affiliation, Major field (mathematics, computers, etc.)

Every 10th bottle of Energized Soda is selected, and the amount of liquid in the bottle is measured. The purpose is to see if the machines that fill the bottles are working properly A.Random B. Systematic C. Stratified D. Cluster

B. Systematic

Ratio Level Example

-Height -Weight -Time -Salary -Age

Name the 4 Types of Measurement Scales

1. Nominal level 2. Ordinal level 3. Interval level 4. Ratio level

The number of touchdowns a quarterback scored each year in his college football career A. Discrete B. Continuous

A. Discrete

The weights of the football players on the teams that play in the NFL this year A. Discrete B. Continuous

B. Continuous

The ratings of bands that played in the homecoming parade at a college A. Nominal B. Ordinal C. Interval D. Ratio

B. Ordinal

Observational Study

The researcher merely observes what is happening or what has happened in the past and tries to draw conclusions based on these observations

Discrete Variables

-Assume values that can be counted must be COUNTABLE -Apart of Quantitative variables -Ex. number of children in a family, number of students in class, number of calls received by a call center each day for a month

Continuous Variables

-Can assume an infinite number of values between any two specific values -Obtained by measuring (often include fractions & decimals) -Ex. Temperature (b/c the variable can assume an infinite number of values between any two given temperatures), and time (b/c it can be measured)

Ordinal Level

-Classifies data in to categories that can ranked; however precise differences between the ranks do not exist -Precise measurement of differences in the ordinal level of measurement DOES NOT EXIST -Type of measurement scale -Ex. T-shirt size, student evaluations (guest speakers might be ranked as superior, average or poor), floats in a homecoming parade might be ranked (1st, 2nd, 3rd place), letter grades (A, B, C, D, F)

Independent Variable

-Is the one that is being manipulated by the researcher -Also called explanatory variable

Dependent Variable

-Is the resultant variable -Also called outcome variable

The number of hours during a week that children ages 12 to 15 reported that they watched television A. Discrete B. Continuous

B. Continuous

Quantitative

-Are variables that can be counted or measured -Classified into two groups: discrete & continuous

Qualitative Variables

-Are variables that have distinct categories according to some characteristic or attribute -Ex. Hair color, soft drink brand, jersey number, religious preference, and geographic location

Nominal level

-Classifies data into mutually exclusive (non-overlapping) categories in which no order or ranking can be imposed on the data -Type of measurement scale -Ex. classifying residents according to zipcode, a car in a parking lot can be classified according to color -Ex. political party, religion, marital status (single, married, divorced, widowed, separated)

Ordinal level Example

-Grades (A, B, C, D, F) -Judging (1st place, 2nd place, 3rd place, etc.) -Rating scale (poor, good, excellent) -Ranking of tennis players

The colors of baseball hats sold in a store for a specific year A. Nominal B. Ordinal C. Interval D. Ratio

A. Nominal

The subscribers to a magazine are numbered. Then a sample of these people is selected using random numbers. A.Random B. Systematic C. Stratified D. Cluster

A.Random

The highest temperature for each day of a specific month A. Nominal B. Ordinal C. Interval D. Ratio

C. Interval

A researcher divides a group of students according to gender, major field, and low, average, and high grade point average. Then she randomly selects six students from each group to answer questions in a survey. A.Random B. Systematic C. Stratified D. Cluster

C. Stratified

Out of 10 hospitals in a municipality, a researcher selects one and collects records for a 24-hour period on the types of emergencies that were treated there. A.Random B. Systematic C. Stratified D. Cluster

D. Cluster

The ages of authors who wrote the hardback versions of the top 25 fiction books sold during a specific week A. Nominal B. Ordinal C. Interval D. Ratio

D. Ratio

Ratio Level

-Posses all the characteristics of interval measurement, and there exists a true zero. In addition, true ratios exist when the same variable is measured on two different members of the population -Types of measurement scale -Ex. If a person has 200 Instagram followers and another person has 100 followers, then not only is there an interval difference of 100 follower, but we can also state the relationship between them as a ratio of 2 to 1. Stated another way, the first person has twice as many followers as the second person. There is also a meaningful zero. If the value of the variable is zero, it implies that a person has no Instagram followers

Interval Level

-Ranks data, and precise differences between units of measure DO exist; however, there is no meaningful zero -Types of measurement scale -NO TRUE ZERO -Ex.Temperature (b/c there is a meaningful difference of 1 degree F between each unit such as 72 and 73 degree F) IQ tests (b/c there is a meaningful difference between an IQ of 109 and an IQ of 110) -Ex. NO TRUE ZERO (IQ tests do not measure people who have no intelligence, & For temperature, 0 degree F does not mean no heat at all)

Interval Level Example

-SAT score -IQ -Temperature

Stratified

-Subjects are selected by dividing up the population into subgroups (strata), and subjects are randomly selected within subgroups -Sampling method -Ex. President at a college wants to learn how students feel about a certain issue. So, the president wants to see if the opinions differ of 1st-year students from 2nd-year students. So, the president randomly select students from each subgroup for the sample

Cluster

-Subjects are selected by using an intact subgroup that is representative of the population -Sampling method -Ex. If there are 10 apartment buildings in the city, the researcher can select at random 2 buildings from the ten to interview

Systematic

-Subjects are selected by using every Kth number after the first subject is randomly selected 1 through K -Sampling method -Ex. Every 10th bottle of energized soda is selected, and the amount of liquid in a bottle is measured

Misuses of Data

-Suspect samples -Ambiguous averages -Changing the subject -Detached statistics -Implied connections -Misleading graphs -Faulty survey questions