An issue with legalization of medical marijuana is “diversion,” the process in which medical marijuana prescribed for one person is given, traded, or sold to someone who is not registered for medical marijuana use. Researchers S. Sautel et al. study the issue of diversion in the article “Medical Marijuana Use Among Adolescents in Substance Abuse Treatment” The mean number of days that 120 adolescents in substance abuse treatment used medical marijuana in the last \6 months was 102.72. Assume the population standard deviation is 32 days.

a. Find a 95% confidence interval for the mean number of days, μ, of diverted medical marijuana use in the last 6 months of all adolescents in substance abuse treatment.

b. Repeat part (a) at a 90% confidence level. 

c. Draw a graph similar to Fig. 8.6 to display both confidence intervals.

d. Which confidence interval yields a more accurate estimate of μ? Explain your answer

Fig. 8.6

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38.0 38.6 We can be 90% confident that μ lies in here 41.4 We can be 95% confident that lies in here " 41.4 44.2 (90% CI) 44.8 (95% CI)