## Business Statistics Glossary for Job Interview

**Analysis of variance (ANOVA): **A procedure for determining how much of the total variability among scores to attribute to a range of sources of variation and for testing hypotheses concerning some of the sources

**Completely randomized design (CRD): **A study in which the assignment of participants to treatment levels is completely random; each participant is in only one treatment condition

**Confidence interval: **A range of values computed from data so that a specified percentage (often 95%) of all possible random samples from the same population will give intervals that contain the true population value

**Correlation coefficient: **A number that represents the degree of association or *strength of the relationship* between two variables

**Critical region: **The *region for rejecting* the null hypothesis; determined by H * _{A}* and α

**Cumulative frequency distribution: **A distribution that shows the number, proportion, or percentage of scores that occur below the real upper limit of each interval *(including all intervals below)*

**Dependent samples: **The selection of participants in one sample is *affected* by the selection of participants in the other sample; keywords “matched” or “repeated”

**Matched sample:** matching each participant in the experimental condition with a participant in the control condition on some variable that is correlated with the dependent variable

**Repeated measures:** observing the same participants under both the experimental and control conditions

**Histogram: **Similar to a bar graph, but used for quantitative variables; constructed by placing vertical bars over the real limits of each interval, with the height of each bar corresponding to the frequency of the interval

**Independent samples: **The selection of participants in one sample is *not affected* by the selection of participants in the other sample; keyword “random”

**Level of significance: **The probability that is the largest risk a researcher is willing to take of rejecting a true null hypothesis

**Mean: ***Average*; sum of the scores divided by the number of scores

**Median: **The *middle value* that divides the data into two equal groups

**Mode: **The score or qualitative category that occurs with the *greatest frequency*

**Normal distribution: **A probability distribution that is *unimodal and symmetrical*; the mean, median, and mode are all the same value (the highest point on the curve)

**Outliers: **Scores that *differ so markedly* from the main body of data that their accuracy is questioned

*p***-value: **The probability of obtaining a value of the test statistic is equal to or more extreme than that observed, given that the null hypothesis is true

**Parameter: **Descriptive measure for a *population*; usually represented by Greek letters

**Percentile (point): **A point on the measurement scale below which a specified percentage of scores falls

**Percentile rank: **The percentage of the scores of the distribution that fall below that score

**Population: **The collection of *all* people, objects, or events having one or more specified characteristics

**Power: **The probability of correctly rejecting the null hypothesis; 1 – β

**Random assignment: **The method of placing participants into the treatment groups in which each participant has an equal chance of being placed in any of the groups

**Random sampling: **The method of drawing samples from a population such that every possible sample of a particular size has an *equal chance of being selected*

**Relative frequency distribution: **A distribution that shows the *proportion or percent frequency* for each interval

**Residual (prediction error): **The difference between a person’s actual score and predicted score

**Sample: **A *subset* of a population

**Sampling distribution: **A probability distribution in which the random variable is a statistic based on the results of more than one trial

**Semi-interquartile range: **Half the distance between the first quartile point and the third quartile point

**Standard deviation: **Measure of the spread of data that is based on every score in a distribution

**Standard score: **A number that expresses the value of a score relative to the mean and standard deviation of its distribution

**Skewed distributions: **Distributions that are *asymmetrical*; there are two types

**Negatively skewed:**longer tail extends to the*left***Positively skewed:**longer tail extends to the*right*

**Statistic: **Descriptive measure for a *sample*; usually represented by English letters

**Type I error: **Rejecting a true null hypothesis

**Type II error: **Retaining a false null hypothesis