A researcher compared the number of cavities of children who had used either Toothpaste brand X or Toothpaste brand Y for a year. At the end of the year, the researcher found that the children who had used brand X has significantly fewer cavities than the children who had used brand Y. The difference was significant at the .05 level. What is the null hypothesis

the null hypothesis states that there is no difference between the number of cavities of children who had used either Toothpaste brand X or Toothpaste brand Y for a year.

Step-by-step explanation:

The null hypothesis is the hypothesis that is assumed to be true. It is an expression that is the opposite of what the researcher predicts.

The alternative hypothesis is what the researcher expects or predicts. It is the statement that is believed to be true if the null hypothesis is rejected.

Looking at the given situation,

The difference was significant at the .05 level. This means that there was enough evidence to reject null hypothesis. Since the null hypothesis contradicts the alternative hypothesis, then the null hypothesis would state that there is no difference between the number of cavities of children who had used either Toothpaste brand X or Toothpaste brand Y for a year.