Agricultural Statistics And Economics Quiz 3 (30 MCQs)

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1. A random sample of 100 visitors to a popular theme park spent an average of $ 142 on the trip with a standard deviation of $ 47.5. Which of the following would be the 98% confidence interval for the mean money spent by all visitors to this theme park?
2. One reason for using a t distribution instead of the standard Normal curve to find critical values when calculating a level C confidence interval for a population mean is that
3. , 31, 37, 46, 29, 38What is the interquartile range of the data?
4. All qualitative variables are measured on a nominal scale.
5. In a crash test of 15 troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $ 1800 and a standard deviation of $ 950. Construct a 99% confidence interval for the repair cost.
6. A keyboarding instructor at a community college collected data comparing a student's age and their typing speed. The equation for the line of best fit is given as:y =-1.4x + 117.8 If you are 25 years of age (x), what is your typing speed (y)?
7. One who provides service to others for a payment is known as-
8. Until the scale was changed in 1995, SAT scores were based on a scale set many years ago. For math scores, the mean under the old scale in the 1990's was 470 and the standard deviation was 110. In 2009, the mean was 515 and the standard deviation was 116. What is the standardized score (z-score) for a student who scored 530 on the old SAT scale?
9. High school textbooks don't last forever. The lifespan of all high school statistics textbooks is approximately Normally distributed with a mean of 9 years and a standard deviation of 2.5 years. What percentage of books last more than 10 years?
10. Scores on a certain standardized test have a mean of 500, and a standard deviation of 100. How common is a score between 600 and 700? Calculate the probability.
11. What is the critical value (t*) for a sample of 55 for 88% confidence?
12. A sample of 20 cupcakes found the interval for calories to be (150, 350). Which is the correct interpretation of the 95% confidence interval?
13. What are the distinguishing features of simple random sampling?
14. In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. Approximately 95% of molds filled by this machine will hold weights in what interval?
15. Learning process, measurement and evaluation, educational studies, environment, management and finance.
16. A quality control specialist at a glass factory must estimate the mean clarity rating for a new batch of glass using a sample of 18 glass sheets from the batch. Past investigations show that clarity ratings are normally distributed. The specialist decides to use a t-distribution rather than a z-distribution because .....
17. ..... defines economics as the study of man in the ordinary business of life.
18. The most fundamental economic problem is
19. Which of the following does NOT have an affect on the width of a confidence interval?
20. A famous medical experiment was conducted by the Nobel Laureate Linus Pauling who believed that vitamin C prevents colds. His subjects were 279 French skiers who were randomly assigned to receive vitamin C or a placebo. Of the 139 given vitamin C, 17 got a cold. Of the 140 given the placebo, 31 got a cold. Find and interpret a 95% confidence interval for the difference of two proportions.
21. Which type of sample does a researcher deliberately set the proportions of levels of members chosen within a sample?
22. Which of the following are true statements? I. Correlation requires that there are clearly-identified explanatory and response variables.II. Scatterplots require that both variables be quantitative.III. Every least-squares regression line passes through $ \left(\overline{x}, \ \overline{y}\right)$
23. The 99% confidence interval for a proportion is (0.54, 0.72). What is the point estimate?
24. When we test np and n(1-p) to ensure they are both greater than or equal to 10, what are we trying to determine?
25. When p-value is greater than alpha we:
26. If 5 is added to every value in a data set, how does this affect the measure of center?
27. Which of the following statement is incorrect?
28. What type of sampling? Twenty-five students are randomly selected from each grade level at a high school and surveyed about their study habits.
29. The correlation between the heights of fathers and the heights of their (fully grown) sons isr = 0.52. This value was based on both variables being measured in inches. If fathers'heights were measured in feet (one foot equals 12 inches), and sons' heights were measuredin furlongs (one furlong equals 7920 inches), the correlation between heights of fathers andheights of sons would be
30. What is the critical value z* for a 99% confidence interval?