The water works commission needs to know the mean househoid usage of water by the residents of a small town in galons per day They would e the estimate to have a maximum error of 0.12 gailons Aprevious study found that for an average family the variance is 5.29 gallons and the mean is 17 galons per day tthey are using a 8S% level of confidence, how large of a sample is required to estimate the mean usage of waterRound your answer up to the next integer Answer Tables Kypad How to enter your answer Keyboard Shortcuts

The weights of students in a large statistics class vary according to a normal distribution with mean 145 pounds and standard deviation 18 pounds What percent of students weigh less than 127 ?

Please solve for p value ,determine weather to reject hypothesis and state the conclusion for enough evidence

The mean and standard deviation of Carbon concentration is 5 mg/L and 2 mg/L based on 25 samples from a river. The mean and standard deviation of Nitrogen concentration is 7 mg/L and 3 mg/L based on 35 samples from the same river. The experimenter wants to answer the question if the Nitrogen concentration is higher than the Carbon concentration. Which of the following methods do you use? Z-test, Default Procedure Z-test, Pooled Variance Procedure T-test, Pooled Variance Procedure T-test, Default Procedure

PLEASE ANSWER ALL THE PARTS OF THE QUESTION ( THIS IS NOT A GRADED ASSIGNMENT)

Please see below. Note that I am only given one attempt at this and I believe that the answer I have may not be correct. In selecting the sample size to estimate the population proportion pp, if we have no knowledge of even the approximate value of the sample proportion p̂ p^, we:A. take two more samples and find the average of their p̂ p^B. let p̂ =0.95p^=0.95C. let p̂ =0.50p^=0.50D. take another sample and estimate p̂ p^ Under which of the following circumstances is it impossible to construct a confidence interval for the population mean?A. A normal population with a large sample and a known population variance.B. A normal population with a small sample and an unknown population variance.C. A non-normal population with a large sample and an unknown population variance.D. A non-normal population with a small sample and an unknown population variance.

Professor Ramos has a packing plant in a machine packs carton with jars. A sales person claims that the machine she is selling will pack faster to test the claim the times It takes each machine to pack 10 cartons are recorded in seconds and the results are shown below population one new machine n=10 Mean =42.3 s=0.685 Present machine n=10 mean=43.23 S =0.750.Do the data provide significant evidence to conclude that on the average the new machine packs faster perform the required hypothesis test in the 5% level of significance assume the population standard deviation's are equal but unknown show all your steps setting up your null  and alternative hypothesis.

A manufacturing process produces a critical part of the average length 110 ​millimeters, with a standard deviation of 2 millimeters. All parts deviating by more than 5 millimeters from the mean must be rejected. What percentage of the parts must be​ rejected, on​ average? Assume a normal distribution.

What are two tools which test how close the dispersion of data matches the distribution shape of a normal curve?

Researcher wanted to determine if carpeted rooms containe more bacteria than uncarpted rooms. Colonies of bacteria were allowed to form in the 16 Petri dishes. A normal probality plot and boxplot indicate that the data are aproximately normally distributed with no outliers.  Do carpted rooms have more bacteria than uncarpted roomz at the a= 0.05 level of signicance?  carpeted rooms (bacteria/cubic foot)   11.8,  8.2, 7.1,  13, 10.8, 10.1 14.6, 14 uncarpted room( bacteria/cubic foot) 12.1, 8.3, 3.8, 7.2, 12, 11.1 10.1 13.7    a) Is this independent or dependent sampling? b) State the null and alternative hypotheses c) P-value:  d) state your conclusion in the langauage of the problem.