If a sample is drawn =, then the sample will follow normal distribution because all the sampling distributions approximately follows the normal distribution with mean, m and standard deviation,
Therefore, the shape of distribution is approximately symmetric.
The mean is same, i.e.
An underground military installation is fortified to the extent that it can withstand up to three
direct hits from air-to-surface missiles and still function. Suppose an enemy aircraft is armed
with missiles, each having a 30 % chance of scoring a direct hit.
i. What is the probability that the installation will be destroyed with the seventh missile fired
is obtained by fewer than nine air strikes?
ii. Find the expected air-to-surface missiles strike.
A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before treatment, 25 subjects had a mean wake time of 104.0 min. After treatment, the 25 subjects had a mean wake time of 94.7 min and a standard deviation of 22.4 min. Assume that the 25 sample values appear to be from a normally distributed population and construct a 99% confidence interval estimate of the mean wake time for a population with drug treatments
(a) Construct the 99% confidence interval estimate of the mean wake time for a population with the treatment.
(b) What does the result suggest about the mean wake time of 104.0 min before the treatment?
(c) Does the drug appear to be effective?