 # DATA ANALYSIS I MKT525. Plan of analysis What decision must be made? What are research objectives? What do you have to know to reach those objectives?

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DATA ANALYSIS I MKT525

Plan of analysis What decision must be made? What are research objectives? What do you have to know to reach those objectives? Now create plan of analysis

SELECTING DATA ANALYSIS TECHNIQUE How many variables will be analyzed at a time? –One variable - univariate analysis –Two variables - bivariate analysis –More than two variables - multivariate analysis

Descriptive Measures Central tendency –Mode –Median –Mean Some Dispersion measures –Range –Standard deviation

Data Set

Inferential Statistics Goal = make inferences about population from sample results Mean of sample usually not = population mean Mean of sampling distribution estimates population mean Variance of sampling distribution depends on population variance, sample size, sample design

Inferential Statistics -2 We only have one sample We can say, based on sample, and with a certain degree of confidence, population mean falls within a certain range of values. Confidence level Standard error of the mean Confidence interval

Inferential Statistics-3 Hypothesis –Null hypothesis = Ho –Alternative hypothesis = H 1 If Ho not rejected, no action taken that is different from current policy - status quo. If Ho rejected, action taken which is different from current policy.

Type I and Type II Errors Type I error: Reject Ho when it is really true. –Probability = alpha = level of statistical significance Type II error: Do not reject Ho when it is really false. –Probability = beta - more difficult to control. Consider which error is more important to keep low.

Issue 1: is sample mean different from a criterion mean? t = sample mean - criterion mean standard error of mean What is sample? Population? What is null hypothesis? Alternative? What is conclusion?

Issue 2: Is a sample proportion different from a criterion proportion? z = sample proportion - criterion proportion standard error of proportion s.e. of prop. = square root of: p(1-p) n What is sample? Population? What is null hypothesis? Alternative? What is conclusion?

Issue 3: Is a frequency distribution different from a criterion distribution? Chi square = Sum (observed - expected) 2 expected What is sample? Population? What is null hypothesis? Alternative? What is conclusion?

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