The sizes of used car loans in a certain state have mean $8452 and standard deviation...
Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.2. a. If the distribution is normal, what is the probability that the sample mean hardness for a random sample of 9 pins is at least 51? b. Without assuming population normality, what is the (approximate) probability that the sample mean hardness for a random sample of 40 pins is at least 51?
Suppose that a random sample of size 64 is to be selected from a population with mean 40 and standard deviation 5. (a) What are the mean and standard deviation of the sampling distribution? (b) What is the approximate probability that will be within 0.3 of the population mean u? (Round your answer to four decimal places.) (c) What is the approximate probability that will differ from u by more than 0.7? (Round your answer to four decimal places.)
Suppose cattle in a large herd have a mean weight of 1158lbs1158lbs and a standard deviation of 92lbs92lbs. What is the probability that the mean weight of the sample of cows would differ from the population mean by less than 12lbs12lbs if 5555 cows are sampled at random from the herd? Round your answer to four decimal places.
The mean salary of people living in a certain city is $37,500 with a standard deviation of $2,041. A sample of 63 people is selected at random from those living in the city. Find the probability that the mean income of the sample is within $500 of the population mean. Round your answer to 4 decimal places.
A population has a mean of 300 and a standard deviation of 80. Suppose a sample size 100 is selected and is used to estimate u. Use z-table. a. What is the probability that the sample mean will be within +/- 5 of the population mean (to 4 decimals)? (Round z value in intermediate calculations to 2 decimal places.) .55 b. What is the probability that the sample mean will be within +/- 11 of the population mean (to 4...
A car insurance company’s repair claims have an unknown mean but a standard deviation of $370. Suppose that the next 16 claims can be regarded as a simple random sample from all their claims. They compute a sample mean based on these 16 claims to estimate the mean of all their claims. They are concerned that the standard deviation of this sample mean is too large. They would like to ensure that their estimate is close to the true mean...
4) Assime that a sample is used to estimate a population mean. Us a confidence level of 95%, a sample size of 60, sample mean of 5.4, and sample standard deviation of 0.93 to find the margin of error. Assume that the sample is a simple random sample and the population has a normal distribution. Round your answer to one more decimal place that the sample standard deviation.
Given a population standard deviation of 40, calculate the standard deviation of the mean (σX) given the following sample sizes (show all your work): 7) N = 60
A population with a mean of 1,250 and a standard deviation of 400 is known to be highly skewed to the right. If a random sample of 64 items is selected from the population, what is the probability that the sample mean will be more than 1,325?
A population has a mean of 400 and a standard deviation of 50. Suppose a sample of size 100 is selected and I is used to estimate u. Use z-table. a. What is the probability that the sample mean will be within +9 of the population mean (to 4 decimals)? b. What is the probability that the sample mean will be within +13 of the population mean (to 4 decimals)? A population proportion is 0.3. A sample of size 300...