Hypothesis testing-confidence interval for cavity prevelance

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Reference no: EM13108290

The producers of a new toothpaste claim that it prevents more cavities than other brands of toothepaste. A random of 60 people used the new toothpaste for 6 months. The mean number of cavities at their next check up is 1.5. In the general population, the mean number of cavities at a 6 month checkup is 1.73 (population mean = 1.12).

a. Is this a one or two tail test?

b. What are Ho and Ha for this study?

c. Compare A obt

d. What is Z cv?

e. Should Ho be rejected? What should fhe researcher conclude?

f. Determine the 95% confidence interval for the population mean, based on sample mean.

A researcher believes the percentage of people who exercise in California is greater than the national exercise rate. The national rate is 20%. The researcher gathers a random sample of 120 individuals who live in CA and finds that the number who exercises regularly is 31 out of 120.

a. What is X2 obt?

b. What is the df for this test?

c. What is X cv? What conclusions can be drawn from these results?

Reference no: EM13108290

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