In a sample of 17 participants,a researcher estimates the 90% CI for a sample with a mean of = 7 and an estimated standard error for the difference scores ( )of 2.2.What is the confidence interval at this level of confidence?
A)90% CI 2.4,11.6
B)90% CI 3.2,10.8
C)90% CI 4.8,9.2
D)There is not enough information to answer this question.

Question

In a sample of 17 participants,a researcher estimates the 90% CI for a sample with a mean of  = 7 and an estimated standard error for the difference scores (  )of 2.2.What is the confidence interval at this level of confidence?
A)90% CI 2.4,11.6 
B)90% CI 3.2,10.8 
C)90% CI 4.8,9.2 
D)There is not enough information to answer this question.

Quizplus · Accepted Answer

The formula to calculate the confidence interval for a mean is:
CI = x̄ ± t*(SE)
where x̄ is the sample mean, t is the critical value from the t-distribution table based on the degrees of freedom (df = n-1) and level of confidence (0.9 for 90% CI), and SE is the estimated standard error of the mean.
Substituting the given values:
CI = 7 ± 1.740*(2.2)
CI = 7 ± 3.832
CI = (7-3.832, 7+3.832)
CI = (3.168, 10.832)
Therefore, the 90% CI is 3.2 to 10.8, which is closest to option B.

In a Sample of 17 Participants,a Researcher Estimates the 90