Please see attached 14 Questions.
An auditor wants to estimate what proportion of a bank's commercial loan files are incomplete. The auditor randomly samples 100 files and finds 9 are incomplete. Using a 95% confidence interval, estimate the true proportion of incomplete files for ALL the bank's commercial loans.
An auditor wants to estimate what proportion of a bank's commercial loan files are incomplete. The auditor wants to be within 4% of the true proportion when using a 95% confidence level. How many files must the auditor sample? No estimate of the proportion is available, so use 0.5 for the population proportion.
If Tom gets a 70 on a physics test where the mean is 65 and the standard deviation is 5.8, where does he stand in relation to his classmates?
A) he is in the bottom 10%
B) he is in the top 10%
C) he is in the bottom 20%
D) he is in the top 20%
Let's assume you have taken 100 samples of size 64 each from a normally distributed population. Calculate the standard deviation of the sample means if the population's variance is 49.
A business wants to estimate the true mean annual income of its customers. It randomly samples 200 of its customers. The mean annual income was $52,500 with a standard deviation of $1,800. Find a 95% confidence interval for the true mean annual income of the business' customers.
In a normal distribution with mu = 25 and sigma = 3 what number corresponds to z = -3?
A) none of these
According to the Central Limit Theorem, how big of a sample is necessary to make sure the sampling distribution of sample means is normally distributed, if we know the underlying population is already normally distributed?
Interpret a 95% confidence interval of (3.355, 3.445) for the population mean.
In the standard normal distribution the mean is always ___
B) none of these
In the standard normal distribution the variance is always ___
B) none of these
The area under the standard normal curve is
C) none of these
An automobile safety engineer wants to estimate the mean cost to repair a Chevy Corvette involved in a 30 mile per hour head-on collision. The engineer crashes 20 Corvettes and finds the mean damage is $16,300 with a standard deviation of $2,330. Find a 95% confidence interval for the true mean cost to repair this type of car.
A business wants to estimate the true mean annual income of its customers. The business needs to be within $500 of the true mean. The business estimates the true population standard deviation is around $2,300. If the confidence level is 95%, find the required sample size in order to meet the desired accuracy.