Question

Use the given degree of confidence and sample data to construct a confidence interval for the population mean H. Assume that the population has a normal distribution. Thirty randomly selected students took the calculus final. If the sample mean was 82 and the standard deviation was 12.6, construct a 99% confidence interval for the mean score of all students. Round to two decimal places. O A. 75.68 < < 88.32 OB. 75.66<u < 88.34 OC. 78.09 < < 85.91 OD. 76.34<u<87.66

Answer 1

of the student score the denote let a with distreibution a normal follows s= 12 6 2 na 30 4= 82 2 given as interval is the confidence (5) <4 < x+ x-t* (s) 0.99 confidence in 0:01 ggf. of freedom 6f) = 30-1 = 29 degree Herce 2.756 found th - we t-table the from 82 - 2.756 (126) <4 a 82 + 2 756 (12:00) + 2 756 x 2.3 cu < 82 2.75642-3 82 - 82 - 6' 3388 su < 82 + 6'3388 75.6612 cu L 88 3388 175.60 cu L 88 34 option (B) is corred