Question

A researcher compared the number of cavities of children who had used either Toothpaste brand M or Toothpaste brand L for a year. At the end of the year, the researcher found that the children who had used brand L had significantly fewer cavities than the children who had used brand M. The difference was significant at the .01 level.

1.         What is the null hypothesis?

2.         What is the research hypothesis?

3.         What would be the Type I error?

4.         What would be the Type II error?

5.         What is the probability of a Type I error?

Answer 1

let  μM and  μL are population mean of cavities in children who had used brand M and L

1)null hypothesis: Ho:μM <=μL

2)research hypothesis μM > μL

3)

type I error:

we conclude that children who had used brand L had significantly fewer cavities than the children who had used brand M while in actual both group chidren have equal number of cavities or Brand M children have less number of cavities

4)

Type II error

we conclude that children who had used brand L had equal number of  cavities as the children who had used brand M while in actual children who had used brand L had significantly fewer cavities than the children who had used brand M.

5)

type I error probability =0.01