Quatitative Questions

1. According to a study several years ago by the personal communications industry association, the just radio phone substance abuser earns $ 62,600 per year. Suppose a researcher believes that the average annual earnings of a wireless phone user are higher like a shot, and he set up a study in an attempt to prove his theory. He every which way samples 48 wireless users and finds out that the average annual wages for this sample is 68,820, with a standard deviation of $7810. office ? = 0.01 to audition the researchers theory. 2. A manufacturing company produces valves in various(a) sizes and shapes. One particular valve plate is supposed to have a tensile strength of 5 pounds per millimetre (lbs/mm). The company tests a random sample of 42 such valves plates from a dress circle of 650 valve plates. The sample mean is a tensile strength of 5.0611 lbs/mm, with a standard deviation of 0.2803 lbs/mm. Use ? = 0.10 and test to determine whether the freshet of valve plates has an average tensile strength of 5 lbs/mm. 3. Figures released by the U.S. department of agriculture show that the average size of farms has increased since 1940. In 1940, the mean size of a farm was 174 acres; by 1997, the average size was 471 acres. Between those years the number of farms diminish but of the amount tillable land remained constant, so now farms are bigger.

This trend might be explained, in part, by the inability of small farms to compete with the prices and costs of large eggshell operations and to produce a level of income necessary to arrest the farmers desired standard of living. Suppose an agriculture researcher believes the average size of farms increased from the 1997 mean reckon of 471 acres. To test this notion, she randomly sampled 23 farms across the United States and discovered the size of each farm from county records. The data she gathered follow. Use a 5% level of significance to test her hypotheses. 489474505553477454463466557502449438 five hundred466477557433545511590561560445 4.... If you want to get a full essay, order it on our website: Orderessay

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