# Exam 2 - Flashcards

## Flashcard Deck Information

 Class: MKTG 4154 - Marketing Research Subject: Marketing University: Virginia Polytechnic Institute And State University Term: Spring 2013
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 Descriptive Statistics describes characteristics of population Inferential Statistics Draws conclusions about whole populations from a sample Frequency Distribution A set of data organized by summarizing the number of times a value occurs Percentage Distribution A frequency distribution organized into a table or graph summarizing % values
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 Probability The long run relative frequency with which an event will occur (adds up to 1) Proportion a percentage of elements that meet some criterion Top-Box scores proportion of respondents who chose the most positive choicethe portion that would most likely recommend a business or make a purchase Deviation scores indicates how far an observation is from the mean
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 Variance A measure of dispersion.its square root is standard deviation Standard deviation The index of distributions spread Normal distribution 99% of its values are within 3 standard deviations from the mean Standardized normal distribution purely theoretical probability distribution that reflects a normal curve for the standardized value, z
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 Characteristics of standardized normal distribution symmetrical about the meanmean identifies that normal curves high point (mode)normal curve has an infinite number of cases (continuous distribution) and area under curve has probability density of 1Has mean of 0 and standard deviation on 1 Standardized values used to compare an individual value to the population mean in units of the standard deviation= value to be transformed- mean / standard deviation Sampling distribution a probability distribution of sample means for all possible samples of a certain size drawn from a particular population Standard error of the mean the standard deviation of the sampling distribution
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 Central limit theorem as a sample size increases, the distribution of approaches normal distribution Point estimates an estimate of the population mean in the form of a single value, usually the sample mean confidence interval estimate a specified range of numbers within which a population mean is expected to lieAn estimate of the population mean based on the knowledge that it will be equal to the sample mean, plus or minus a small sampling error Confidence level a percentage that tells how confident a researcher can be about being correcttraditionally, researchers use 95% confidence level with 5% tolerance of error
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 Random sampling error varies with samples of different sizes diminishing returns a random sampling error is inversely proportional to the square root of n heterogenous/homogenous heterogeneous population: has more variance and requires a larger sampleHomogeneous population: has less variance, a smaller standard deviation, and permits a smaller sample Magnitude of error aka confidence intervalHow precise must an estimate be?
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 sequential sampling conducting a pilot study to estimate the population parameters so that another, larger sample of appropriate size may be drawn
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## List View: Terms & Definitions

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Descriptive Statisticsdescribes characteristics of population
Inferential StatisticsDraws conclusions about whole populations from a sample
Frequency DistributionA set of data organized by summarizing the number of times a value occurs
Percentage DistributionA frequency distribution organized into a table or graph summarizing % values
ProbabilityThe long run relative frequency with which an event will occur (adds up to 1)
Proportiona percentage of elements that meet some criterion
Top-Box scoresproportion of respondents who chose the most positive choice
• the portion that would most likely recommend a business or make a purchase
Deviation scoresindicates how far an observation is from the mean
VarianceA measure of dispersion.
• its square root is standard deviation
Standard deviationThe index of distributions spread
Normal distribution99% of its values are within 3 standard deviations from the mean
Standardized normal distributionpurely theoretical probability distribution that reflects a normal curve for the standardized value, z
Characteristics of standardized normal distribution
2. mean identifies that normal curves high point (mode)
3. normal curve has an infinite number of cases (continuous distribution) and area under curve has probability density of 1
4. Has mean of 0 and standard deviation on 1
Standardized valuesused to compare an individual value to the population mean in units of the standard deviation

= value to be transformed- mean / standard deviation
Sampling distributiona probability distribution of sample means for all possible samples of a certain size drawn from a particular population
Standard error of the meanthe standard deviation of the sampling distribution
Central limit theoremas a sample size increases, the distribution of approaches normal distribution
Point estimatesan estimate of the population mean in the form of a single value, usually the sample mean
confidence interval estimatea specified range of numbers within which a population mean is expected to lie
• An estimate of the population mean based on the knowledge that it will be equal to the sample mean, plus or minus a small sampling error
Confidence levela percentage that tells how confident a researcher can be about being correct
• traditionally, researchers use 95% confidence level with 5% tolerance of error
Random sampling errorvaries with samples of different sizes
diminishing returnsa random sampling error is inversely proportional to the square root of n
heterogenous/homogenousheterogeneous population: has more variance and requires a larger sample
Homogeneous population: has less variance, a smaller standard deviation, and permits a smaller sample
Magnitude of erroraka confidence interval
How precise must an estimate be?
sequential samplingconducting a pilot study to estimate the population parameters so that another, larger sample of appropriate size may be drawn