Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard deviation (s) = 7.54.
A) 99% CI = 96.55 ± 3.19
B) 99% CI = 96.55 ± 2.64
C) 99% CI = 96.55 ± 4.32
D) 99% CI = 96.55 ± 4.55

Question

Calculate the 99% confidence interval for a sample of N = 24 with a mean  = 96.55 and standard deviation (s) = 7.54.
A) 99% CI = 96.55 ± 3.19 
B) 99% CI = 96.55 ± 2.64 
C) 99% CI = 96.55 ± 4.32 
D) 99% CI = 96.55 ± 4.55

Quizplus · Accepted Answer

To calculate the 99% confidence interval, we use the formula:

99% CI = X̄ ± (t_critical)*(s/√n)

where X̄ is sample mean, s is sample standard deviation, n is sample size, and t_critical is the t-score from the t-distribution table with (n-1) degrees of freedom and 99% confidence level.

Plugging in the values, we get:

99% CI = 96.55 ± (2.797)*(7.54/√24)

99% CI = 96.55 ± 4.32

Therefore, the answer is C.

Calculate the 99% Confidence Interval for a Sample of N