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thirty randomly selected students took the calculus final. if the sample mean wa

ID: 3156098 • Letter: T

Question

thirty randomly selected students took the calculus final. if the sample mean was 90 and the standard deviation was 13.9, construct a 99% confidence interval fir the mean score of all students thirty randomly selected students took the calculus final. if the sample mean was 90 and the standard deviation was 13.9, construct a 99% confidence interval fir the mean score of all students thirty randomly selected students took the calculus final. if the sample mean was 90 and the standard deviation was 13.9, construct a 99% confidence interval fir the mean score of all students

Explanation / Answer

Confidence Interval
CI = x ± t a/2 * (sd/ Sqrt(n))
Where,
x = Mean
sd = Standard Deviation
a = 1 - (Confidence Level/100)
ta/2 = t-table value
CI = Confidence Interval
Mean(x)=90
Standard deviation( sd )=13.9
Sample Size(n)=30
Confidence Interval = [ 90 ± t a/2 ( 13.9/ Sqrt ( 30) ) ]
= [ 90 - 2.756 * (2.538) , 90 + 2.756 * (2.538) ]
= [ 83.006,96.994 ]