Find a 90% confidence interval for the difference between the population means for the two locations, assuming that the populations are approximately normally distributed.
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A: Solution: Assumptions for constructing a confidence interval on the difference between means are…
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A: Given: Degree of freedom = 25 α = 1 - 0.95 = 0.05
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A: Given that for a fixed sample size. We have to find what happens to a confidence interval for mu…
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A: We consider the studentized version of x to develop a confidence-interval procedure for a population…
Q: Find the critical value, for a 90% confidence when the sample size is 22.
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A: Given CL = 0.90 Population variance, σ2=4 Sample size, n=8 9,14,10,12,7,13,11,12
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A: When we use z instead of t in, it will result in a smaller margin of error and consequently narrower…
Q: Find the 98% confidence interval for the difference between the means of the two populations
A: Given that sample size n = 18 Mean difference = 22.9 And SD sd = 2.2 The critical value of t at (n -…
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Q: If one hundred 98% confidence intervals are constructed for a population parameter, we would…
A: Confidence interval : It is a range of estimates for an unknown parameter.
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A: As per our guidelines, we can solve only the first question. Kindly repost the other question for…
Q: Everything else being equal, a population with more variability yields a confidence interval that…
A: It is very useful in statistics . It has wide applications in all hypothesis testing problems .
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Q: An interval estimate with a 99% confidence means that there is 0.99 probability that the population…
A: We have to interpret the confidence interval.
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A: Given: The error margin for 98% confidence internal for the average value of Y when X is 9
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A: Given : n = 25 x¯=54 S = 12
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A: Solution
Q: Find the critical value, for a 90% confidence when the sample size is 22
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A: Confidence interval: The (1-α) % confidence interval for population standard deviation is given by:
Q: Find a 90% confidence interval for the mean if a sample of size 12 has a mean = 34.2 and the…
A: The sample size is 12, sample mean is 34.2, and sample standard deviation is 8.5. The degrees of…
Q: for a sample size of 12 and a 90% confidence interval, the t statistic used to estimate U would be.
A: Given: Sample size = 12 Confidence interval= 90%
Q: b. Construct a confidence interval suitable for testing the claim that the two samples are from…
A: Since population standard deviations are unknown, the appropriate confidence interval is is…
Q: Find a 95% confidence interval that contains the population variance if a sample of 41 generates a…
A: Given : sample varience s^2=25 and sample size n=41 then to find 95% confidence interval of…
Q: For a fixed sample size, what happens to a confidence interval for u when we increase the level of…
A: Here we need to determine whether the width of the confidence interval becomes narrower or wider…
Q: Construct a 99% confidence interval for the population standard deviation σ if a sample of size 8…
A: Confidence interval: The (1-α) % confidence interval for population standard deviation is given by:
Find a 90% confidence interval for the difference between the population means for the two
locations, assuming that the populations are approximately
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- Unfortunately, arsenic occurs naturally in some ground water. A mean arsenic level of m= 8.0 parts per billion (ppb) is considered safe for agricultural use. A well in Texas is used to water cotton crops. This well is tested on a regular basis for arsenic. A random sample of 37 tests gave a sample mean of xbar= 7.2 ppb arsenic, with s= 1.9 ppb. Does this info indicate that the mean level of arsenic in this well is less than 8ppb? Use a= 0.01. Show full detail.The intelligence quotients (IQs) of 16 students from one area of a city showed a mean of 107 and a standard deviation of 10, while the IQs of 14 students from another area of the city showed a mean of 112 and a standard deviation of 8. Use alpha = 0.01. What is the pooled standard deviation?A regulation lacrosse ball should weigh 154 grams. A company produces lacrosse balls for the PLL. To help ensure a high degree of accuracy, a random sample of 20 lacrosse balls is drawn from the production line every 45 minutes and each lacrosse ball is measured for accuracy. If the average weight of the sample is found to be significantly different than 154 grams, then the production line is shut down for inspection. The mean weight of a recent sample of 20 lacrosse balls was found to be 167.98 grams. Use the p-value method to test the hypothesis that the mean weight of a lacrosse ball produced by this company is different than 154 grams, using α=0.02α=0.02. Assume that the distribution of weights of all lacrosse balls produced by this company is known to be approximately normally distributed with a standard deviation of 21.6 grams. State the null and alternative hypothesis for this test. H0= H1= Determine the test statistic for the hypothesis test. Round the solution to two decimal…
- The coating thickness of plastic film in millimeters (mm) on a substrate material is tested using two difference temperatures which are 125°F and 150°F. The substrate material with temperature of 125°F is normally distributed with a mean coating thickness of 103.5mm and a standard deviation of 10.2mm. While the substrate material with temperature of 150°F also are normally distributed with a mean coating thickness of 99.7mm and a standard deviation of 16.imm. Random samples of 11 substrates are coated at 125°F and 13 substrates are coated at 150°F. a) Construct the sampling distribution of the difference in means of coating thickness between two temperatures. b) Find the probability that the mean coating thickness for temperature of 125°F exceed 110mm.A commercial on Station A has a mean length of 35 seconds with a standard deviation of 8 seconds. Station B has a mean commercial length of 30 seconds with a standard deviation of 5 seconds. Compare the relative dispersion of the two stations.Unfortunately, arsenic occurs naturally in some ground water. A mean arsenic level of mu equals 8.0 parts per billion (ppb) is considered safe for agricultural use. A well in Texas is used to water cotton crops. This well is tested on a regular basis for arsenic. A random sample of 36 test gave a sample mean of x-bar = 6.9 ppb arsenic, with s = 2.6 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Alpha = 0.01. a) What is the level of significance? b) What is the value of the sample test statistic? Round answer to 3 decimal places. c) estimate the p-value?
- A soft-drink machine is regulated so that the amount of drink dispensed averages 240 milliliters with a standard deviation of 15 milliliters. Periodically, the machine is checked by taking a sample of 40 drinks and computing the average content. If the mean of the 40 drinks is a value within 2 standard deviations from the mean , the machine is thought to be operating satisfactorily; otherwise, adjustments are made. If the company official found the mean of 40 drinks to be 236 milliliters and concluded that the machine needed no adjustment. Was this a reasonable decision?Avalanches can be a real problem for travelers in the western United States and Canada. Slab avalanches studied in Canada had an average thickness of µ = 67 cm. A sample of 31 avalanches in the U.S. gave a sample mean of = 63.0 cm. It is known that o = 10.3 cm for this type of data. Use a 0.03 level of significance to test the claim that the mean slab thickness of avalanches in the United States is different from that in Canada. Use the P-Value Approach. What is the Decision for this problem? O There is not sufficient evidence at the 0.03 level of significance to show that the mean slab thickness of avalanches in the United States is different from that in Canada. There is sufficient evidence at the 0.03 level of significance to show that the mean slab thickness of avalanches in the United States is less than that in Canada. There is sufficient evidence at the 0.03 level of significance to show that the mean slab thickness of avalanches in the United States is different from that in…