MyMathLab Lauren Hutten Quiz Chap 8 Quiz 102215 922PM Time R

MyMathLab Lauren Hutten Quiz: Chap 8 Quiz 10/22/15 9:22PM Time Remaining: 00:52.01 Submit Quz This Question: 6 pts 20110(10 compete) This Quiz: 15 pts possible oh seling prices of a ,DApersonal dgtal ass start, n eighteen raidornty dosen stres are shown stores are shown below 226 25 234 246 215 15 20 244 238 226 246 22 250 246 257 206 212 244 175 250 These data have x-23322. s= 21 02, Q1: 226, Modan: 241-a3-246 Use StatCrunch to find the requested summary statistics and confidence intervals b. Determine the 95% confidenco interval for the population mean The lower limit is The upper limit is (Round to two decimal places as needed.) Interpret this confidence interval We can be 95% confident that the mean population price is between $22277 and $24367 Ninety-five percent of prices tall between S222.77 and $243 67 We can be 95% confident that all seling prices are between S222T7 and$24367 we can be 95% confident that a avon seling proe will be between S222. 77 and$243 67 O A. B. OC. OD, Click to select your answers).

Solution

b)

Note that              
Margin of Error E = t(alpha/2) * s / sqrt(n)              
Lower Bound = X - t(alpha/2) * s / sqrt(n)              
Upper Bound = X + t(alpha/2) * s / sqrt(n)              
              
where              
alpha/2 = (1 - confidence level)/2 =    0.025          
X = sample mean =    233.22          
t(alpha/2) = critical t for the confidence interval =    2.109815578          
s = sample standard deviation =    21.02          
n = sample size =    18          
df = n - 1 =    17          
Thus,              
Margin of Error E =    10.45300008          
Lower bound =    222.7669999 [ANSWER]
Upper bound =    243.6730001 [ANSWER]]

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b)

OPTION A: We can be 95% confident that the mean population price is between 222.77 and 243.67. [ANSWER]