A schoolteacher is worried that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L. The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. At a 5% significance level, the decision is to ________. A) reject H₀; we can conclude that the mean concentration of radon gas is greater than the safe level B) reject H₀; we cannot conclude that the mean concentration of radon gas is greater than the safe level C) not reject H₀; we can conclude that the mean concentration of radon gas is greater than the safe level D) not reject H₀; we cannot conclude that the mean concentration of radon gas is greater than the safe level

Question

Quizplus · Accepted Answer

The sample mean of 4.4pCi/L is higher than the safe level of 4pCi/L, and with a standard deviation of 1pCi/L over 36 days, a t-test can be used to determine if this difference is statistically significant at the 5% level. Given the information, rejecting the null hypothesis (that the mean concentration is not greater than the safe level) is appropriate, indicating the mean concentration of radon gas is statistically significantly greater than the safe level.

A Schoolteacher Is Worried That the Concentration of Dangerous, Cancer-Causing