A coin-operated drink machine was designed to discharge a mean of 7 ounces of coffee per cup. In a test of the machine, the discharge amounts in 12 randomly chosen cups of coffee from the machine were recorded. The sample mean and sample standard deviation were 7.02 ounces and o0.2 ounces, respectively. If we assume that the discharge amounts are normally distributed, is there enough evidence, at the 0.05 level of significance, to conclude that the true mean discharge, µ, differs from 7 ounces? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the alternative hypothesis H. 0: 'H H, :0 (b) Determine the type of test statistic to use. O=0 Oso D20 (Choose one) (c) Find the value of the test statistic. (Round to three or more decimal places.) ? (d) Find the two critical values. (Round to three or more decimal places.) O and O (e) At the 0.05 level of significance, can we conclude that the true mean discharge differs from 7 ounces? OYes ONo Ix

The size of the left upper chamber of the heart is one measure of cardiovascular health. When the upper left chamber is enlarged, the risk of heart problems is increased. A paper described a study in which the left atrial size was measured for a large number of children aged 5 to 15 years. Based on these data, the authors concluded that for healthy children, left atrial diameter was approximately normally distributed with a mean of 26.2 mm and a standard deviation of 4.1 mm. (Round your answers to four decimal places.) A USE SALT (a) Approximately what proportion of healthy children have left atrial diameters less than 24 mm? (b) Approximately what proportion of healthy children have left atrial diameters greater than 32 mm? (c) Approximately what proportion of healthy children have left atrial diameters between 25 and 30 mm? (d) For healthy children, what is the value for which only about 20% have a larger left atrial diameter? mm

A triathlon consisting of swimming, cycling, and running is one of the more strenuous amateur sporting events. An article reports on a research study involving nine male triathletes. Maximum heart rate (beats/min) was recorded during performance of each of the three events. For swimming, the sample mean and sample standard deviation were 187.0 and 7.2, respectively. Assuming that the heart-rate distribution is (approximately) normal, construct a 98% CI for true mean heart rate of triathletes while swimming. (Round your answers to one decimal place.) USE SALT beats/min You may need to use the appropriate table in the Appendix of Tables to answer this question.

The distribution of the student heights at a large college is approximately bell shaped. If the mean height is 66 inches,and approximately 95% of the heights fall between 32 and 100 inches, then, the standard deviation of the heightdistribution is approximately equal to

In a certain country the heights of adult men are normally distributed with a mean of 70.2 inches and a standard deviation of 2.7 inches. The​ country's military requires that men have heights between 66 inches and 79 inches. Determine what percentage of this​ country's men are eligible for the military based on height. The percentage of men that are eligible for the military based on height is nothing​%. ​(Round to two decimal places as​ needed.)

We want to estimate the mean distance travelled to work by employees of a large manufacturing firm. Past studies indicate that the variance of these distances is 4.0 km2and that the distances follow a normal distribution. How many employees should be chosen at random and polled if the estimated mean distance is to be within 0.1 km ofthe true mean with a confidence level of 95%?

The president of a college wants to determine the mean number of units that college students take per semester. How large of a sample is required in order to be 99% sure that a sample mean will be off by no more than 1.25 units? An initial study suggested that the standard deviation is approximately 2.1 units.

In a study of birth order and intelligence, IQ tests were given to 18- and 19-year-old men to estimate the size of the difference, if any, between the mean IQs of firstborn sons and secondborn sons. The following data for 10 firstborn sons and 10 secondborn sons are consistent with the means and standard deviations reported in the article. It is reasonable to assume that the samples come from populations that are approximately normal. Can you conclude that the mean IQ of firstborn sons is greater than the mean IQ of secondborn sons? Let μ1 denote the mean IQ of firstborn sons and μ2 denote the mean IQ of secondborn sons. Use the α = 0.01 level and the P-value method with the table. Firstborn 128 101 128 112 121 105 122 98 106 108 Secondborn 121 125 110 107 114 93 80 94 91 83 Part(a): State the appropriate null and alternate hypotheses. H0:   H1: This is a _____…

The means of the number of revolutions per minute of two competing engines are to be compared. Thirty engines are randomly assigned to be tested. Both populations have normal distributions. Table 10.4 shows the result. Do the data indicate that Engine 2 has higher RPM than Engine 1? Test at a 5% level of significance. Engine      Sample Mean Number of RPM         Population Standard Deviation  1                      1,500                                                       50  2                      1,600                                                       60