What is the difference between a sample and a population?
A sample refers to a group of people who are chosen for the study, and are intended to represent the whole population; a population is every person with the trait or quality specified. Ex. Specified trait = UR College student. Sample = 10 randomly selected student from UR. Population = everyone at UR.
100
What are the 4 Scales of Measurement?
Nominal, Ordinal, Interval and Ratio scales
100
What are the 4 types of frequency data organization tables?
Frequency distribution, bar graph, histogram and frequency polygon.
100
What is the difference in the mean formula between a sample and a population?
In a sample mean formula, the mean is represented by X bar. In a population mean formula, the mean is represented by μ.
100
What is the definition of a measure of variation?
A measure that demonstrates how spread out the data is around the mean.
DAILY DOUBLE: What are the three measures of variation?
200
What are the 3 Goals of Science? Name research method for each.
Description - observational, case study or survey method; Prediction - correlational, quasi-experimental method or alternative explanation; Explanation - experimental method
200
What are the 4 Properties of Measurement?
Absolute Zero, Equal Unit Size, Identity and Magnitude
DAILY DOUBLE: As the scales of measurement become more specific, certain properties of measurement are added. At which scale of measurement is each property of measurement added?
200
What is the difference between a frequency distribution and a class interval distribution?
A frequency distribution lists every recorded level or score and has the frequency of that answer beside it. A class interval distribution groups the levels or scores into sections or intervals and has the frequency of answers within the range.
200
“A numerical measures that describe a distribution by providing information on the central tendency, width and shape of the distribution.” What is this definition describing?
Descriptive statistics.
200
In a study, the range of heights measured spanned from 58 inches to 79 inches, with a mean of 71.3, and a median of 67.9. What kind of distribution will this data have?
A Positively Skewed Distribution.
300
“In a study of UR students, it was found that as the minutes per week spent at the gym increased, the students’ BMI decreased.” This is an example of what kind of correlational relationship?
Negative relationship - as one variable increases, the other decreases.
DAILY DOUBLE: What research method is this and for which goal of science does it work?
300
What is a continuous variable? What type of data is usually continuous?
A variable that can be broken down into fractional amounts. Ex. Weight - 112.8 lbs, 167.3 lbs. Interval and Ratio data are usually continuous.
300
What sort of data does a bar graph represent?
Data that is discrete and nominal in scale. Ex. hair color. This describes a qualitative variable.
300
What is the mean, median and mode of this sample:
2, 5, 9, 11, 7, 1, 4, 8, 7, 24, 6, 8, 30
Mean = 9.38, Median = 7, Mode = 7 & 8
300
What is the difference between the average deviation formula and standard deviation formula?
In AD, the absolute value is taken of the score - mean. In STD, the whole equation is square rooted.
400
What is the only type of research that can infer causation?
Experimental method
400
What is a discrete variable? What type of data is usually discrete?
A variable that is broken down into whole-number units or categories. Ex. Ethnicity. Nominal and Ordinal data are usually discrete.
400
What sort of data does a histogram represent?
Data that is continuous; and ordinal, interval or ratio in scale. Ex. test scores. This describes a quantitative variable.
400
Which measure of central tendency is only effectively used for nominal data?
Mode - used with all four kinds of ratio scales, including nominal.
DAILY DOUBLE: For what kind of data are the other two measures of central tendency used?
400
What changes in the formula for STD between STD of a population and STD of a sample?
μ (mean) becomes x bar (sample mean), σ (STD) becomes S (sample STD).
500
What aspect of the design of experimentation makes it different from any other research method?
“The researcher controls as much as possible in order to determine whether there is a cause-and-effect relationship between the variables being studied.” Statistics: Plain and Simple pg. 7
500
What type of measurement scale and variable is applicable for the data set “number of children per family”?
The data set fits into a Ratio scale because it is has an identity (number of kids), magnitude (a finding of 2 represents more kids than a finding of 1), equal unit size (the difference between 2 kids and 3 kids is that same as the difference between 3 kids and 4 kids) and absolute zero (a finding of 0 means the family has no kids). However, the data represents a discrete variable because the data is measured in whole-number units, ie. you can’t have .6 of a kid.
500
A frequency polygon represents the same data as what other type of data organization table?
A histogram - a frequency polygon represents the frequency of a quantitative variable, but instead of visually representing the data in bars, the frequency polygon has a line.
500
“In an intro level psychology class of 25 students, the distribution of scores on the first exam was such that the lowest score was a 52%, the 13th was a 78% and the 25th was a 91%.” What measure of central tendency is this example highlighting?
Median - even though the range between the bottom and middle of the class was much larger than the middle and top of the class, the 78% was the median because it was the central score of the 25 students, once the scores were ordered.
500
What statistic does this formula give?
Σ|score - mean|
_____________
# of scores
Average deviation
DAILY DOUBLE: What is the definition of the average deviation?