SOLUTION: The results of a national survey showed that on average, adults sleep 6.5 hours per night. Suppose that the standard deviation is 1.3 hours and that the number of hours of sleep f
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-> SOLUTION: The results of a national survey showed that on average, adults sleep 6.5 hours per night. Suppose that the standard deviation is 1.3 hours and that the number of hours of sleep f
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Question 1145302: The results of a national survey showed that on average, adults sleep 6.5 hours per night. Suppose that the standard deviation is 1.3 hours and that the number of hours of sleep follows a bell-shaped distribution. If needed, round your answers to two decimal digits. If your answer is negative use “minus sign”.
(a) Use the empirical rule to calculate the percentage of individuals who sleep between 3.9 and 9.1 hours per day.
Enter your answer as a percentage.
%
(b) What is the z-value for an adult who sleeps 8 hours per night?
(c) What is the z-value for an adult who sleeps 6 hours per night?
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You can put this solution on YOUR website! (a) Use the empirical rule to calculate the percentage of individuals who sleep between 3.9 and 9.1 hours per day.
Enter your answer as a percentage.
3.9 hours and 9.1 hours are exactly two standard deviations below/above the mean. (One standard deviation is 1.3, so two standard deviations are 2.6. The mean is 6.5, and 2.6 below the mean is 3.9, and 2.6 above the mean is 9.1.) Using the empirical rule, that means 95% of individuals sleep between 3.9 hours and 9.1 per day. (b) What is the z-value for an adult who sleeps 8 hours per night? = = +1.15 (c) What is the z-value for an adult who sleeps 6 hours per night? = = -0.38
