Random Sample n = 58
Standard deviation = 0.000965
Mean = 0.3193
Confidence interval when is known given by = * /
Where is normal table value at level of significance .
For = 1 - 0.98 = 0.02
/ 2 = 0.01
Value of is 2.3263 ( can be found from Normal table or any other software like R)
by using R
{
>
qnorm(1-0.02/2) #
values of
[1] 2.326348
}
To calculate 100(1-)% or 98 % percent confidence interval for true mean metal thickness is given by -
CI = * / = 0.3193 2.3263 * 0.000965 /
= 0.3193 0.0002947671
Thus 98 % percent confidence interval for true mean metal thickness is - ( 0.3190 , 0.3196 ) { round to four decimals }
98 % percent confidence interval is from 0.3190 to 0.3196
The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that...
The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000943 mm. Assume a random sample of 58 sheets of metal resulted in an x¯ = .2603 mm. Calculate the 99 percent confidence interval for the true mean metal thickness. (Round your answers to 4 decimal places.) The 99% confidence interval is from to
The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000631 mm. Assume a random sample of 46 sheets of metal resulted in an x bar = .3293 mm. Calculate the 90 percent confidence interval for the true mean metal thickness. (Round your answers to 4 decimal places.) The 90% confidence interval is from to