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The scores on the Wechsler Intelligence Scale for Children (WISC) are thought to be Normally distributed with a standard deviation of 10.
A simple random sample of 25 children is taken, and each is given the WISC.
The mean of the 25 scores is 104.32.

Based on these data, what is a 95% confidence interval for true mean score?

Respuesta :

Answer: Interval would be (100.4,108.24).

Step-by-step explanation:

Since we have given that

Standard deviation = 10

Mean = 104.32

N = 25

We need to find 95% confidence interval.

At 95% confidence interval, z = 2.58

So, interval would be

[tex]\bar{x}\pm z\dfrac{\sigma}{\sqrt{n}}\\\\=104.32\pm 1.96\times \dfrac{10}{\sqrt{25}}\\\\=104.32\pm \dfrac{19.6}{5}\\\\=104.32\pm 3.92\\\\=(104.32-3.92,104.32+3.92)\\\\=(100.4,108.24)[/tex]

Hence, interval would be (100.4,108.24).

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