A lumber company is making boards that are 2701.02701.0 millimeters tall. If the boards are too long they must be trimmed, and if they are too short they cannot be used. A sample of 2222 boards is made, and it is found that they have a mean of 2703.92703.9 millimeters with a variance of 100.00100.00. Is there evidence at the 0.10.1 level that the boards are either too long or too short? Assume the population distribution is approximately normal. Is there sufficient evidence to support the claim that the boards are either too long or too short?

Consider the following data: −11,−5,−5,−11,13,−11,−5−11,−5,−5,−11,13,−11,−5 Copy Data Step 2 of 3:  Calculate the value of the sample standard deviation. Round your answer to one decimal place.

The Food and Drug Administration has determined that a substance called Melamine poses a health threat when it contaminates food. In fact, it poses a health threat even to dogs when it is in their food. Consequently, the FDA wants to monitor shipments of dog food imported into the country. From previous studies on dog food, the FDA knows that the population mean of Melamine in dog food is 8.0 grams in a 40 pound bag, with a population standard deviation of 1.5 grams. How likely would it be that a random sample of 36 40-pound bags of dog food would have a mean of more than of 8.4 grams of Melamine per bag? All bags have at least 8 grams 0.05 0.50 None of the bags will have less than 8 grams

You may need to use the appropriate appendix table or technology to answer this question. Studies show that massage therapy has a variety of health benefits and it is not too expensive. A sample of 14 typical one-hour massage therapy sessions showed an average charge of $58. The population standard deviation for a one-hour session is a - $5.5. (a) What assumptions about the population should we be willing to make if a margin of error is desired? We should be willing to make the assumption that the population is at least approximately uniform. We should be willing to make the assumption that the population is at least approximately normal. We should be willing to make the assumption that the population is at least approximately skewed right. We should be willing to make the assumption that the population is at least approximately bimodal. We should be willing to make the assumption that the population is at least approximately skewed left. (b) Using 95% confidence, what is the margin of…

High-power experimental engines are being developed by the Stevens Motor Company for use in its new sports coupe. The engineers have calculated the maximum horsepower for the engine to be 600HP600⁢HP. Nine engines are randomly selected for horsepower testing. The sample has an average maximum HP of 610610 with a standard deviation of 50HP50⁢HP. Assume the population is normally distributed.   Step 1 of 2 :   Calculate a confidence interval for the average maximum HP for the experimental engine. Use a significance level of α=0.05�=0.05. Round your answers to two decimal places.

Mj

I have a distribution with mean zero and variance of 9.  I sample 4 people from the population.  What is my standard error? Round to 3 decimal points.

A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 1010 nursing students from Group 1 resulted in a mean score of 55.755.7 with a standard deviation of 7.97.9. A random sample of 1515 nursing students from Group 2 resulted in a mean score of 65.665.6 with a standard deviation of 6.16.1. Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let μ1�1 represent the mean score for Group 1 and μ2�2 represent the mean score for Group 2. Use a significance level of α=0.05�=0.05 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 3 of 4:…

Not sure what is the next step

Question: In a certain factory there are two independent processes manufacturing the same item. The average weight in a sample of 250 items produced from one process is found to be 120 ozs. with a standard deviation of 12 ozs. while the corresponding figures in a sample of 400 items from the other process are 124 and 14. Obtain the standard error of difference between the two sample means. Is this difference significant ? Also find the 99% confidence limits for the difference in the average weights of items produced by the two processes respectively.