Use the following to answer the questions below:
On August 8, 2012, the national average price for a gallon of regular unleaded gasoline was $3.63. The prices for a random sample of gas stations in the state of Illinois were recorded at that time. The mean price for the sampled gas stations was $3.975, with standard deviation $0.2266. A boxplot of the data is provided.

-Construct a 95% confidence interval for the mean gas price in Illinois (on August 8, 2012). Round your margin of error to three decimal places.
A) 3.813 to 4.137
B) 3.822 to 4.128
C) 3.807 to 4.143
D) 3.791 to 4.159

Question

Use the following to answer the questions below:
On August 8, 2012, the national average price for a gallon of regular unleaded gasoline was $3.63. The prices for a random sample of gas stations in the state of Illinois were recorded at that time. The mean price for the sampled gas stations was $3.975, with standard deviation $0.2266. A boxplot of the data is provided.
 
-Construct a 95% confidence interval for the mean gas price in Illinois (on August 8, 2012). Round your margin of error to three decimal places.
A) 3.813 to 4.137 
B) 3.822 to 4.128 
C) 3.807 to 4.143 
D) 3.791 to 4.159

Quizplus · Accepted Answer

df = 9
3.975 ± 2.262 11eeb2d3_8e0c_c90a_b9aa_2994490d5333_TBW1049_11 
3.975 ± 0.162
3.813 to 4.137

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