Hypothesis Testing 9. An advertisement for a new toothpaste claims that it reduces cavities of children in their cavity-prone years. Cavities per year for this age group are normal with mean 3 and...

Hypothesis Testing
9. An advertisement for a new toothpaste claims that it reduces cavities of children in

their cavity-prone years. Cavities per year for this age group are normal with mean 3 and

standard deviation 1. A study of 2500 children who used this toothpaste found an

average of 2.95 cavities per child. Assume the standard deviation of the number of

cavities of a child using this new toothpaste remains equal 1.
a) Are these data strong enough, at the 5% level of significance, to establish a claim of

the toothpaste advertisement?
b) Do the data convince you to switch to this new toothpaste?