A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before​ treatment, 19 subjects had a mean wake time of 101.0min. After treatment, the 19 subjects had a mean wake time of 72.4 min and a standard deviation of 21.8 min. Assume that the 19 sample values appear to be from a normally distributed population and construct a 99​% confidence interval estimate of the mean wake time for a population with drug treatments. What does the result suggest about the mean wake time of 101.0min before the​ treatment? Does the drug appear to be​ effective?

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step-by-step explanation:

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step-by-step explanation:

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is