The scores of a certain population on the Wechsler Intelligence Scale for Childr
ID: 2957909 • Letter: T
Question
The scores of a certain population on the Wechsler Intelligence Scale for Children (WISC) are thought to be Normally distributed with mean and standard deviation = 10. A simple random sample of 25 children from this population is taken and each is given the WISC. The mean of the 25 scores is = 104.32.
Based on these data, a 95% confidence interval for is
104.32 ± 0.78.
104.32 ± 3.29.
104.32 ± 3.92.
104.32 ± 19.60
The scores of a certain population on the Wechsler Intelligence Scale for Children (WISC) are thought to be Normally distributed with mean and standard deviation = 10. A simple random sample of 25 children from this population is taken and each is given the WISC. The mean of the 25 scores is = 104.32.
Based on these data, a 95% confidence interval for is
104.32 ± 0.78.
104.32 ± 3.29.
104.32 ± 3.92.
104.32 ± 19.60
Explanation / Answer
Given Mean =104.32
standard deviation =10
sample size n=25
At 95% confidence, critical value is 1.96
Therefore confidence interval is given by ±1.96(/n)
=104.32±1.96(10/25)
=104.32±1.96*2
=104.32±3.92
So the required answer is 104.32±3.92