A team of researchers (Singer et al., 2000) used the Survey of Consumer Attitudes to investigate whether incen- tives would improve the response rates on telephone surveys. A national sample of 735 households was randomly selected, and all 735 of the households were sent an "advance letter" explaining that the household would be contacted shortly for a telephone survey. However, 368 households were randomly assigned to receive a monetary incentive along with the ad- vance letter, and the other 367 households were assigned to receive only the advance letter. Here are the data on how many households responded to the telephone survey.

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