State the Null Hypothesis (as a sentence) State the Alternative Hypothesis (as a

Question

State the Null Hypothesis (as a sentence)

State the Alternative Hypothesis (as a sentence)

Show all work for each problem.

Report your conclusion (Do you retain or reject the Null? And what does that mean in terms of the problem? That is, you should write a verbal conclusion that relates back to the actual problem)

Problem: A local homeless shelter hopes to increase its holiday donations during the Christmas season. It pilot tests three different approaches during the Thanksgiving season. The shelter calls 12 past donors using one of three approaches. In the control condition, potential donors are called and simply asked whether they would be willing to contribute money to provide meals for homeless people during Thanksgiving. In the consistency condition, people are thanked for their previous donations – the consistency manipulation – and are then asked whether they would be willing to contribute to provide meals for homeless people during Thanksgiving. In the consistency + door in the face condition, people are thanked for their previous contributions and then asked whether they would be willing to contribute $500 for meals for homeless people during Thanksgiving. When the caller gets turned down, he/she asks for a smaller contribution – that’s the door in the face technique. Shown below are the contributions for the 12 pilot test subjects. Did the type of approach used in the phone call have a significant impact on contributions? Assume we used alpha = .05 and a critical value of 4.26.

           

Control                                               25        30        20        50

             Consistency                                       40        50        55        35       

             Consistency + Door in Face               75        60        40        50

Explanation / Answer

H0 : The population means of all three groups are same.

Ha : At least one population mean is different.

Here the mean and varaince table

Here grand mean = (31.25 + 45 + 56.25)/3 = 41.1667

so SS(Between groups) = 4 * (31.25 - 41.1667)2 + 4 * (45 - 41.16667)2 + 4 * (56.25 - 41.1667)2 = 1254.167

dF (Withing groups) = 3 -1 = 2

MSW = 1254.167/2 = 627.0833

SS(Withing Groups) = (4-1)* 172.9167 + (4-1) * 83.3333 + (4 -1) * 222.9167 = 1437.5

DF(error) = 9

MSE = 1437.5/9 = 159.7222

F = MSW/MSE = 627.0833/159.7222 = 3.926

so here F < Fcritical

so we can say that none of the mean is different from each other. THere is no effect of approach used in the phone call have a significant impact on contributions

SUMMARY Groups Count Sum Average Variance Control 4 125 31.25 172.9167 Consistency 4 180 45 83.33333 Consistency+ door in face 4 225 56.25 222.9167

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