# Statistical help ...20

1Solid fuel is packed in sacks which are then weighed on scales. It is known that the weight of full sack is normally distributed with mean kg and standard deviation 0.36 kg. Four randomly selected sacks were weighted and the results were: 34.7, 34.4, 35.1 and 34.6 kg respectively.

(a)Calculate the 95% confidence interval for .

(b)State the sampling error of estimate with 95% confidence.

(c)How many full sacks have to be weighed so that there is 95% confidence that the error is within 0.15kg?

(a)Calculate the 95% confidence interval for μ

### 2 個解答

• 7 年前
最愛解答

yoyo, mean 係咪 μ (mu)?

So as part (a).

2013-11-16 22:14:29 補充：

OK, 我差不多可以幫你解答了～

你的 95% sampling error, notes 是否教你用 2*1.96*σ/√n ?

2013-11-16 22:15:03 補充：

還是只是用 1.96*σ/√n ?

2013-11-16 22:27:41 補充：

定係你只用 σ/√n ?

2013-11-16 22:49:02 補充：