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ts of Statistics lewis connolly& Quiz: Unit 7: Quiz Time Remaining: 01:35:07 Sub

ID: 2906901 • Letter: T

Question

ts of Statistics lewis connolly& Quiz: Unit 7: Quiz Time Remaining: 01:35:07 Submit Quia This Question: 2 pts This Quiz: 20 pts possibl m. First use the range rule of thumb to make a rough estimate of the standard deviation A student wants to estimate the mean score of all college students for a particular exa of those scores. Possible scores range from 500 to 2200. Use technology and the estimated standard deviation to determine the sample size confidence level and a margin of error of 100 points. What isn't quite right with this exercise? corresponding to a 95% The range rule of thumb estimate for the standard deviation is (Type an integer or a fraction.) A confidence level of 95% requires a minimum sample size of (Round up to the nearest integer.) What isn't quite right with this exercise? OA. A marain of error of 100 points seems too high to provide a good estimate of the mean score /22/2018

Explanation / Answer

Solution :

Given that margin of error E = 100 , possible scores range from 500 to 2200

=> The range rule of thumb estimate for the standard deviation is 425.

=> ? = range ÷ 4

= (2200 – 500) ÷ 4

= 425

=> A confidence level of 95?% requires a minimum sample size of 69

=> For 95% confidence interval , Z = 1.96

=> Sample size n = [ (z * ?) ÷ E ]^2

= [ (1.96 × 425) ÷ 100 ]^2

= 69.3889

= 69 (nearest integer)

=> A margin of error of 100 points seems too high to provide a good estimate of the mean score.