Use the given information to find the number of degrees of freedom, the critical values χ2L and χ2R, and the confidence interval estimate of σ. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. Nicotine in menthol cigarettes 99% confidence; n=23, s=0.28 mg.
df = (Type a whole number.)
χ2L = (Round to three decimal places as needed.)
χ2R = (Round to three decimal places as needed.)
The confidence interval estimate of σ is mg < σ < mg. (Round to two decimal places as needed.)

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fichoh fichoh · Answer 1 · 2021-07-30T12:26:21+02:00

Answer:

χ²R = 8.643

χ²L = 42.796

0.20 < σ < 0.45

Step-by-step explanation:

Given :

Sample size, n = 23

The degree of freedom, df = n - 1 = 23 - 1 = 22

At α - level = 99%

For χ²R ; 1 - (1 - 0.99)/2= 0.995 ; df = 22 ; χ²R = 8.643

For χ²L ; (1 - 0.99)/2 = 0.005 ; df = 22 ; χ²L = 42.796

The confidence interval of σ ;

s * √[(n-1)/χ²L] < σ < s * √[(n-1)/χ²R)]

0.28 * √(22/42.796) < σ < 0.28 * √(22/8.643)

0.2008 < σ < 0.4467

0.20 < σ < 0.45