According to the Public Health Service (PHS), the optimal concentration of fluor

Question

According to the Public Health Service (PHS), the optimal concentration of fluoride in public water supplies is 0.70 mg/L. Suppose that Alicia is an environmental scientist who is testing the quality of tap water a small city, and she believes that officials are not adding enough fluoride to the water supply. Alicia tests the water from 60 randomly selected residences and finds that the mean fluoride concentration is 0.66 mg/L, with a standard deviation of 0.27 mg/L. Her data look normally distributed, so she decides to perform a t-test to determine if the mean fluoride level is significantly lower than the PHS recommendation. She chooses a significance level of 0.05. Alicia calculates the one-sample t-statistic to be 1.15, which results in a p-value of 0.13.

What should Alicia conclude based on her t-test result?

Explanation / Answer

SInce the p-value is 0.13 which is greater than the significance level of 0.05, She fails to reject the nully hypothesis.

There is no conclusive proof that the officials are not adding enough fluoride to the water and alicia cannot conclusively reject their claim

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