Term
| What are the four types of measurements? |
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Definition
| Nominal, ordinal, interval, and ratio |
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Term
| Define the nominal measurement type |
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Definition
| Values represent categories or qualities of a case only (i.e. male or female) |
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Term
| Define the ordinal measurement type |
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Definition
| Values not only represent categories but also have a logical order (i.e. income being in ranges, not exact amounts) |
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Term
| Define the interval measurement type |
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Definition
| In addition to an inherent rank order, a value's relationship to other values is known. There is an equal and constant distance between adjacent values (i.e. the Fahrenheit temperature scale with it's arbitrary zero) |
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Term
| Define the ratio measurement type |
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Definition
| Not only can distances be determined between values, but these distances are based on a true zero point (i.e. income level by exact dollar amount) |
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Term
| What is descriptive research? |
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Definition
| Describing a social phenomenon of interest in terms of "who, what where, and when" |
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Term
| What is explanatory research? |
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Definition
| That which seeks to identify causes and effects of phenomena |
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Term
| What is evaluation research? |
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Definition
| That which considers the implementation and effects of social policies and programs |
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Term
| What is measurement validity? |
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Definition
| The accuracy of one's measurements |
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Term
| What is causal validity (aka interval validity)? |
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Definition
| The truthfulness of an assertion that A causes B. |
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Term
| What is generalizability? |
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Definition
| The extent to which the study can be used to inform us about the general population |
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Term
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Definition
| The larger set of cases or aggregate number of people that a researcher is actually interested in |
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Term
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Definition
| A subset of a population that is measured to learn about the population as a whole |
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Term
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Definition
| Any difference between the characteristics of a sample and the population from which it was taken |
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Term
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Definition
| A probability sample where every element of a population has an equal chance of being selected |
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Term
| Describe systematic random samples |
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Definition
| The first element is selected randomly, but instead of continuing randomly sampling, the researcher systematically chooses the rest of the sample (like selecting every 5th person on a random list of offenders) |
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Term
| What is a multistage cluster sample? |
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Definition
| Selecting elements of interest from naturally occurring groups (like cities, states, or countries) |
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Term
| Describe a weighted sample |
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Definition
| Instead of having an equal chance of being selected, individuals would have a known but unequal chance of being selected |
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Term
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Definition
| Designating the population into proportions of some group that you would like in your sample |
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Term
| Describe a purposive or judgement sample |
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Definition
| When the researcher uses his or her own judgement to select who goes into the sample |
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Term
| Describe an availability sample |
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Definition
| Based solely on the availability of the respondents (like surveys posted on websites) |
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Term
| Describe a frequency distribution |
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Definition
| The entire set of values a variable takes on |
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Term
| Give the formula for a rate |
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Definition
| Rate = (# in subset ÷ total #) x constant (e.g. 1,000) |
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Term
| What is the formula for a proportion? |
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Definition
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Term
| What are real class limits? |
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Definition
| Class intervals that are continuous (have no gaps between the intervals) |
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Term
| What is the formula to find the midpoint in a data set? |
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Definition
| m = (lower limit + upper limit) ÷ 2 |
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Term
| A normal distribution is one that is... |
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Definition
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Term
| A negatively skewed distribution is one that leans to the... |
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Definition
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Term
| A positively skewed distribution is one that leans to the... |
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Definition
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Term
| What is the formula for the percent change scores? |
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Definition
| % Change = ((finish value - start value) ÷ start value) x 100 |
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Term
| To smooth a data set, one uses a ______ average, which takes the average of three or more points and shifts as it continues along the data points |
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Definition
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Term
| What is a measure of central tendency? |
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Definition
| A summary descriptive statistic that captures the most typical score in a distribution |
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Term
| The mode average conceptualizes central tendency in terms of what? |
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Definition
| What is the most likely (or most common) score in a distribution |
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Term
| A bimodal distribution is one that contains ___ distinct modes |
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Definition
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Term
| What is a median average? |
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Definition
| A score at the 50th percentile in a rank-order distribution of scores |
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Term
| How does one find the median in a data set? |
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Definition
-First, rank order the data
-Then, find the POSITION of the median score using this formula: (n +1) ÷ 2. Remember, this is the POSITION of the median, not the actual median |
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Term
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Definition
| The arithmatic average of a group of scores. It is the appropriate measure of central tendency for interval/ratio level data |
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Term
| How does one find the mean? |
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Definition
| Sum the scores of the data and divide by the number of scores |
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Term
| The symbol for mean of a data set is ___ while the symbol for the mean of a population is ___ |
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Definition
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Term
| How would one find the mean from a grouped frequency distribution? |
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Definition
-Multiply each midpoint by its frequncy
-Sum the obtained products from the first step
-Divide this by the total number of scores |
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Term
| What is the purpose of measures of dispersion? |
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Definition
| They capture how different values of a variable are. The more dispersion there is in a variable, the more different the values are or the more heterogeneity in the data |
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Term
| What is a variation ratio? |
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Definition
| A measure of dispersion appropriate for nominal or ordinal data. It measures the extent to which values do not fall within the modal category. The greater the value, the more dispersion |
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Term
| What formula does one use to find the variation ratio? |
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Definition
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Term
| What is the range of a data set? |
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Definition
| A measure of dispersion appropriate for interval/ratio level data |
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Term
| How does one find the range of a data set? |
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Definition
| Range = Highest value - lowest value |
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Term
| What is the interquartile range? |
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Definition
| A measure of dispersion that measures the range of scores in the middle 50 percent of a distribution of continuous scores |
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Term
| How does one measure the interquartile range? |
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Definition
| Score at the 3rd quartile - score at the first quartile |
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Term
| What is a mean deviation? |
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Definition
| The distance between a score and the mean of the group of scores |
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Term
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Definition
| The average of the squared deviations from the mean |
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Term
| What is the standard deviation? |
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Definition
| The square root of the squared deviations about the mean |
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Term
| Describe how to find the sample variance |
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Definition
1- Calculate the mean
2- Subtract the mean from each score (take the deviation)
3- Square the deviation of each score from the mean
4- Sum the squared deviations for all scores
5-Divide that by the number of scores minus 1 |
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Term
| Describe how to find the sample standard deviation |
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Definition
1- Calculate the mean
2- Subtract the mean from each score (take the deviation)
3- Square the deviation of each score from the mean
4- Sum the squared deviations for all scores
5-Divide that by the number of scores minus 1
6- Take the square root of this |
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Term
| What is the difference between taking the standard deviation from grouped and ungrouped data? |
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Definition
| The mean is assumed to be the midpoint of each class interval in grouped data |
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Term
| The probability of an event is defined as... |
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Definition
| The number of times A can occur over the total number of events |
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Term
| What is the formula for probability? |
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Definition
| P(a) = Number of times a can occur ÷ total number of possible events |
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Term
| The bounding rule of probabilities states that any event... |
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Definition
| Can never be less than zero nor greater than 1 |
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Term
| How does one calculate the odds of an occurrence? |
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Definition
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Term
| Mutually exclusive events are... |
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Definition
| Events that cannot occur at the same time |
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Term
| The restricted addition rule of probability states that... |
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Definition
If two events are mutually exclusive, the probability of event A occurring or event B occurring is equal to the sum of their separate probabilities
P(A or B) = P(A) + P(B) |
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Term
| What is the formula to find the probability of one of two mutually exclusive events occurring? |
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Definition
| P(A or B) = P(A) + P(B) - P(A and B) |
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Term
| What formula is used to determine the probability of two independent events both occurring? |
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Definition
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Term
| What is the probability of two dependent events occurring together? |
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Definition
| P(A and B) = P(A) x P(B∣A) |
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Term
| How can one tell if two events are independent of one another? |
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Definition
| When the unconditional probability of A is equal to the conditional probability of A given B |
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Term
| What is a probability distribution? |
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Definition
| A theoretical distribution of what one SHOULD observe |
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Term
| What is the formula for the binomial coefficient? |
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Definition
P(r) = (n! ÷ (r!(n-r)))p^r x q^n-r
p = success
q = failure (or 1 - p)
r = probability of some number of sucesses |
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Term
| What is the null hypothesis? |
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Definition
| The assumption that there is no relationship between the variables |
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Term
| The difference between a directional alternative hypothesis and a nondirectional is that the directional... |
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Definition
| Assumes that not only is the null hypothesis wrong, but that the right answer lays in a certain direction away from the null hypothesis |
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Term
| What is a type I and type II error? |
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Definition
Type I: when one rejects a null hypothesis that is really true
Type II: when one fails to reject a null hypothesis that is false |
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Term
| What is a level of significance (aka alpha level? |
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Definition
| The level of risk of being wrong a researcher is willing to take |
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Term
| What is the critical region? |
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Definition
| The entire class of outcomes in a probability distribution that will lead one to reject the null hypothesis |
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Term
| How does one calculate the z score? |
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Definition
z = (x - x̄) ÷ s
x = raw score
x̄ = sample mean
s = standard deviation |
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Term
| What is the standard error of the mean? |
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Definition
The standard deviation of the sampling distribution
σ subx̄ = σ ÷ √n |
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Term
| The central limit theorem states... |
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Definition
| If an infinite number of random samples of size n are drawn from any population with mean µ and standard deviation σ, then as the sample sizes gets larger, the sampling distribution of means approaches normality |
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Term
| How does one calculate the confidence interval? |
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Definition
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Term
| How does one calculate the confidence interval of a proportion? |
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Definition
| Confidence interval = p ± zsub∝ (σsub p) |
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