# Cell Size by bud19087

VIEWS: 9 PAGES: 13

• pg 1
```									             How to Calculate the Minimum Size of Control/Mail Cell Required

Estimated response rate of Control/Mail Cell:                                                        1.500%
low
Allowable margin of error:                                                                          0.150%           1.350%
(Note: Margin of error above is preset - this can be changed based upon your own marketing experience - see "Margin of Error Calculation" tab for instruction

ANSWER - MINIMUM SIZE OF CONTROL/MAIL CELL:                                                            25,227          @a

How to use this sheet:
- fill out the estimated response rate of the Control/Mail Cell in the yellow cell which currently reads 1.500%
- if you are unsure of the estimated response rate, enter several values to see how Control/Mail Cell size will be affected
- the allowable margin of error is currently fixed at a default of 10% of the response rate
- if you have historical data that differs significantly from 10%, please revise the formula in cell B6 to reflect it

The minimum size of the Control/Mail Cell will automatically be calculated in cell B8.

Value for VLOOKUP
1.960

Confidence Level

90%
95%
ell Required

high
1.650%
rgin of Error Calculation" tab for instructions)

95%       confidence level

Mail Cell size will be affected

ell B6 to reflect it

Value for VLOOKUP
1.960

Confidence Level   Value

90%         1.645
95%          1.96
How to Determine if the Incremental Response Rate
is Statistically Significant

MAIL GROUP INFORMATION:
Size of the mail group (# names mailed)
Response rate of the mail group (% response)

CONTROL GROUP INFORMATION:
Size of the control group (# names)
Response rate of the control group (% response)

ENTIRE UNIVERSE INFORMATION:
Size of the universe (mail + control)
Response rate of the universe (mail + control)

Confidence Level
And the final number is ....
And the benchmark that you compare the number to is ...

ANSWER - IS THE INCREMENTAL RESPONSE RATE SIGNIFICANT?

How to use this sheet:
- fill out the actual size of the mail group in the yellow cell that currently reads 200,000
- fill out the actual response rate of the mail group in the yellow cell that currently reads 1.500%
- fill out the actual size of the control group in the yellow cell that currently reads 250,000
- fill out the actual response rate of the control group in the yellow cell that currently reads 1.650%

The test for statistical significance in the incremental response rate will automatically be
calculated in cell B17. If the word "YES" appears in cell B20, then this means that the
mail cell had a significant difference in response rate over the control cell. If the word
"NO" appears in cell B20, then the incremental response rate is not statistically significant
and the results of the direct mail are inconclusive.

Benchmarks
95% Confidence Level = 1.96
90% Confidence Level = 1.645
Confidence Level
90%
95%
ate

200,000
1.500%

250,000
1.650%

450000
1.583%

95%
4.005
1.960

YES

significant
Confidence Level   Value
90%   1.645
95%    1.96
Response
Confidence                     Rate
Level
1 – response rate

E=
Population
Illustrative formula above uses a 95% confidence level

Confidence level:                   95%                 Start Here with drop down menu
Response Rate                     0.75%
Population                       25,000

Margin of Error                  0.107%
Value for VLOOKUP

1.960

Confidence Level       Value

90%             1.645
95%              1.96