# Hypothesis Testing & Confidence Interval for Cavity Prevelance

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.

https://brainmass.com/statistics/type-i-and-type-ii-errors/hypothesis-testing-confidence-interval-for-cavity-prevelance-575414

#### Solution Preview

Answer

a. Is this a one or two tail test?

This is a one tailed test and is a lower tailed test.

b. What are Ho and Ha for this study?

Ho: Mean number of cavities at a 6 month checkup >= 1.73 (mu >= 1.73)

Ha: Mean number of cavities at a 6 month checkup < 1.73 (mu < 1.73)

c. Compare A obt

Z ...

#### Solution Summary

The solution provides step by step method for the calculation of test statistics, confidence intervals and hypothesis types for two given research scenarios. All steps shown with almost 200 words of explanation throughout.