Answer:
765,795 = 96%
Step-by-step explanation:
confidence interval = 0.04
The Za/2 theorem = 1/2 = 0.04/2 = 0.02= /x = 720z
If ; 0.02 = 2.05 then the interval is 780-2.05 x 40/√30 x 780+2.05 x 30/√30 = 765,795 = 96%
We see 40/ √30 which is found in equation of finding the sample mean at point /x = 720z
σ 40/ n√30 = 7.3029674334 and is simply a fraction of /x 720z
By normal distribution we find
The 96% confidence interval for the population mean of all bulbs = 765,795
As 765, x 1.04 = 795 = 765, 795
To find Sampling mean.
The Sampling Distribution of the Sample Mean. If repeated random samples of a given size n are taken from a population of values for a quantitative variable, where the population mean is μ (mu) and the population standard deviation is σ (sigma) then the mean of all sample means (x-bars) is population mean μ (mu).
Confidence Level z*-value
80% 1.28
90% 1.645 (by convention)
95% 1.96
96% 2.05
98% 2.33
99% 2.58
