# Verification for Solve of Zobt Please

• Jan 11th 2013, 06:05 AM
Gentleman019
Post Solved Please Ignore. Thank you.
This is a pretty straightforward problem but I am still learning. Please take a quick look and see if this was done correctly. Thank you.Problem: The producers of a new toothpaste claim that it prevents more cavities than other brands of toothpaste. A random sample of 60 people used the new toothpaste for six months. The mean number of cavities at their next checkup is 1.5. In the general population, the mean number of cavities at 6-month check-up is 1.73 (σ = 1.12). Solutionz_obt= (M-μ)/σ-M = (1.5-1.73)/1.12= -0.205Thank you.
• Jan 11th 2013, 04:01 PM
chiro
Re: Verification for Solve of Zobt Please
Hey Gentleman019.

What is the standard deviation or standard error of the new cavity trial sample? Are they the same? (ie 1.12 for both sigma or standard errors)?

Your test statistic is not correct: You need to take into account the number of samples as well as both standard errors or standard deviations.

Do you know the formula to calculate a test statistic for a two sample t-test?