Perry Drake of Drake Direct is interviewed by "Search Marketing Standard" magazine regarding the state of SEM education in major universities. To see this interview, click on the artilces link below....................................................Drake Directs latest DMA presentation on Test Design can bee seen by clicking on the presentation link below.
A/B Split Test - Sample Size Estimation - Confidence Interval Estimation - Multivariate Test - Drake Direct

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Receive Your Free Sampling Error/Sample Size Estimator Card Today!

Keep one of these handy credit card sized estimators in your purse or wallet for use during meetings or when a quick reference is needed. With these sample size estimator cards you can:
  • Estimate the amount of error in your A/B split or multivarite test results at both the 90% and 95% confidence interval levels

  • Determine how large of a sample is required to ensure your test will be readable, reliable and projectable
Each card comes with easy to follow instructions on the back of the card and is laminated for durability.

For example, the amount of error associated with a test response rate of 1.60% and a sample size of 10,000 is .21% -- implying the actual response rate in rollout can be as low as 1.39% or as high as 1.81% with 90% probability (as shown in the red circle).

Get yours today, no obligation.
To received your free sample size estimator card today, simply send a self-addressed #10 envelope with one affixed 39 cent stamp to:

Drake Direct
Sample Size Card Offer
225 East 46th Street, Penthouse D
New York, NY 10017


Please allow 2-4 weeks for delivery.


Drake Direct, 225 East 46th Street, Penthouse D, New York, NY 10017, Phone: (212) 759-1225 Fax: (212) 759-9756