Question

In a study designed to test the effectiveness of acupuncture for treating migraine, 142 subjects

Answer 1

Answer:

Option a) 1.6 .

Step-by-step explanation:

We are given that  142 subjects  were treated with acupuncture. The numbers of migraine attacks for the treatment group had a  mean of 1.8 and a standard deviation of 1.4 which means;

Sample Mean, $xbar$ = 1.8   ,  Sample standard deviation, s = 1.4   and  Sample size = 142.

Now, 95% confidence interval estimate of the mean number of migraine attacks for all people treated with acupuncture is given by;

                                 $xbar \pm 1.96 *\frac{s}{\sqrt{n} }$

                           ⇒ $1.8 \pm 1.96 *\frac{1.4}{\sqrt{142} }$

So, the lower bound = $1.8 - 1.96 *\frac{1.4}{\sqrt{142} }$ = 1.56 ≈ 1.6

Therefore, option A is correct.