In a survey of buying habits, 400 women shoppers are chosen at random in super market 'A' located in a certain section of the city. Their average weekly food expenditure is dollar 250 with a standard deviation of Dollar 40. For 400 women shoppers chosen at random in super market 'B' in another section of the city, the average weekly food expenditure is Dollar 220 with a standard deviation of Dollar 55. Test at 1% level of significance whether the average weekly food expenditure of the two populations of shoppers are equal.

Americans spend an average of 23.6 hours per week online, with a standard deviation of 7. The distribution of internet watching is not necessarily normally distributed. Suppose you took a random sample of 50 people. What is the probability that the sample average will be less than 23 hrs? Round your answer to three decimal places, eg 0.628.

The average and standard deviation of the amount of GST paid by all sole trader businesses in Australia in a twelve month period were $5.602 thousand and $1.637 thousand respectively. If a sample of 120 sole trader businesses was chosen, find the sample average value above which only 15% of sample averages would lie. Give your answer in dollars (to the nearest dollar).

An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 4.34.3 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 280280 engines and the mean pressure was 4.44.4 pounds/square inch. Assume the variance is known to be 0.640.64. A level of significance of 0.050.05 will be used. Make a decision to reject or fail to reject the null hypothesis.    Make a decision.

Please answer correctly

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.

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 810HP . Sixteen engines are randomly selected for horsepower testing. The sample has an average maximum HP of 890 with a standard deviation of 85HP . 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=0.01 . Round your answers to two decimal places.

The probability of a sample proportion this high coming from a population where the true proportion of Pennsylvanians with a high school diploma is 83% is 0.0228. How convincing is this probability in convincing us that the true proportion of Pennsylvanians with a high school diploma is greater than 0.83?

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

During an evolution, the minimum, maximum, and average fitness of a population is 1.2, 270, and 40, respectively. If the most fit individual is to be 3 time more likely than the average fit individual to be selected, and the least fit individual is 1/3 as likely as the average fit individual to be selected, what is the scaled fitness of an individual whose raw fitness is 58.