Consumer Reports (Sept. 1992) evaluated and rated 46 brands of toothpaste. One attribute examined in the study was whether or not a toothpaste brand carries an American Dental Association (ADA) seal verifying effec-

tive decay prevention.The data for the 46 brands (coded 1 = ADA seal, 0 = no ADA seal) are listed here.

a. Give the null and alternative hypotheses for testing whether the true proportion of toothpaste brands with the ADA seal verifying effective decay prevention is less than .5.

b. The data were analyzed in SPSS; the results of the test are shown in the SPSS printout below. Interpret the results.