Question

Has the mean age of the onset of anorexia nervosa in women been decreasing? The previous...

Has the mean age of the onset of anorexia nervosa in women been decreasing? The previous mean age is 15 years. A sample of 20 women showed a mean age of 14.250 years with a standard deviation of 1.512 years. Construct a 95% confidence interval for the mean age of the onset of anorexia nervosa.

Math   Statistics-And-Probability   
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Answer #1

Solution :

Given that,

t /2,df = 2.093

Margin of error = E = t/2,df * (s /n)

= 2.093 * (1.512 / 20)

Margin of error = E = 0.708

The 95% confidence interval estimate of the population mean is,

- E < < + E

14.250 - 0.708 < < 14.250 + 0.708

13.542 < < 14.958

(13.542 , 14.958)

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