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- A nail is needed to hang up a 50 lb painting on a wall. A technician has two nails in his pocket, where the probability that both nails meet the specific weight of the painting is 50%, the probability that only one of them meets the specific weight is 20%, and the probability that neither of them meets the specific weight is 30%. If the number of nails that meet the specification is a random variable, find the variance of the data of that random variable.The aim of a study is to test the ratio of variances in the weight of two groups of rats being under a certain drugs A ( group 1) and B ( group 2) . A random sample of 16 rats was selected from group land 13 rats from group 2, Then their weight were recorded. The results are shown in the following table n Mean Median sd group 1 16 3.5 3.0 1.05 group 2 13 2.20 2.0 1.15 F15,12,0.05 =0.404 F19,16,0.025 = 0.386| F16,10,0.025 =0.335 F16,10,0.05 =0.401| F15,12,0.1 = 0.496 | F19,16,0.05 =0.451 F10,16,0.025 =0.286 F12,15,0.05 =0.382 F16,19,0.025 =0.371 F10,16,0.05 =0.354 F12,15,0.1=0.475 F16,19,0.05 = 0.437 Construct a 95% confidence interval for the ratio of the variances. [ Hint: because of the rounding select the closest interval ] O a. None of these O b. [ 2.488, 0.238 ] O c. [ 2.160 , 0.309 ] O d. [2.063 , 0.318]One sample has n=7 and SS=35 and a second sample has n =17 and SS =45. What is the pooled variance for these two samples?
- The aim of a study is to test the ratio of variances in the weight of two groups of rats being under a certain drugs A ( group 1) and B ( group 2) . A random sample of 16 rats was selected from group land 13 rats from group 2, Then their weight were recorded. The results are shown in the following table n Mean Median sd group 1 16 3.5 3.0 1.05 group 2 13 2.20 2.0 1.15 F15,12,0.05 = 0.404 F 19,16,0.025 = 0.386 F16,10,0.025 =0.335| F16,10,0.05 =0.401 F15,12,0.1 =0.496 F19,16,0.05 =0.451 F10,16,0.025 = 0.286 F 12,15,0.05 =0.382 F16,19,0.025 = 0.371| F10,16,0.05 = 0.354 F12,15,0.1 =0.475 F16,19,0.05 = 0.437| Construct a 95% confidence interval for the ratio of the variances. [ Hint: because of the rounding select the closest interval ] O a. None of these O b. [ 2.488, O0.238 ] O c. [ 2.160 , 0.309] O d. [2.063 , 0.318]If two samples are selected from the same population, under what circumstances will the two samples have exactly the same t statistic? Question 4 options: If the samples are the same size and have the same variance If the samples are the same size and have the same mean If the samples have the same mean and the same variance If the samples are the same size and have the same mean and the same variance1. A population has the numbers 2, 4, 6, 8, 10, 12. Then two samples are taken at random and without replacement. If it is known µ-7. Find: a. Population variance (0²) b. The mean standard deviation of the sample (ox²)
- The nation of Olecarl, located in the South Pacific, has asked you to analyze international trade patterns. You first discover that each year it exports 10 units and im- ports 10 units of wonderful stuff. The price of exports is a random variable with a mean of 100 and a vari- ance of 100. The price of imports is a random variable with a mean of 90 and a variance of 400. In addition, you discover that the prices of imports and exports have a correlation of r = -0.40. The prices of both ex- ports and imports follow a normal probability density function. Define the balance of trade as the difference between the total revenue from exports and the total cost of imports. What are the mean and variance of the balance of trade? What is the probability that the balance oft trade is negative?For a Poisson random variable, what is the relationship between its parameter and its mean?Example 1 Calculate Variance and Standard Deviation of the following lengths in inches using nge of origin method. 30, 28, 25, 27, 20, 20, 24, 27, 19, 15, 9
- A transect is an archaeological study area that is mile wide and 1 mile long. A site in a transect is the location of a significant archaeological find. Let x represent the number of sites per transect. In a section of Chaco Canyon, a large number of transects showed that x has a population variance . In a different section of Chaco Canyon, a random sample of 23 transects gave a sample variance for the number of sites per transect. Use an to test the claim that the variance in the new section is greater than 36.4. What is the level of significance? 90% 1% 5% 95% 10%Suppose a researcher pbserves a population of 12 people and computes SS=204. What is the variance? What is the standard deviation?A company is doing a hypothesis test on the variation of quality from two suppliers. They believe that one of the suppliers has a different variance than the other supplier and would like to perform a hypothesis test to support their claim. Both distributions are normal, and the populations are independent. use a = 0.01 Ho :012 = 0 2 ² HA:012 =0 2 2 Supplier 1: standard deviation = 2.82, Sample size = 35 Supplier 2: standard deviation = 3.18, Sample size = 18. The test statistic (rounded to 4 decimal places) is = The p-value (rounded to 4 decimal places) is = O Reject the null hypothesis - there is enough evidence is support a meaningful difference in the variance of the suppliers. O Fail to reject the null hypothesis - there is not enough evidence to support a meaningful difference in the variance of the suppliers.