A cosmetics company claims that teenage ladies consume an average of Php 150 monthly for cosmetic products. In order to verify this claim, a researcher conducted a survey to 40 teenage ladies and...

A cosmetics company claims that teenage ladies consume an average of Php 150 monthly for cosmetic products. In order to verify this claim, a researcher conducted a survey to 40 teenage ladies and found that their mean monthly expense for cosmetic products is Php 146 with standard deviation of Php 12. Using α=0.05, test whether the companies claim is realistic or not?