• Example: Suppose that the variance o² of the normally distributed diameter lengths of steel balls produced in a factory is unknown. The sample variance of n = 12 steel balls taken from a population was calculated as s² = 0.022cm². Then create a 90% confidence interval for the variance of ball diameters.
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A: From the provided information, Population mean (µ) = 54.3 miles/gallon Population variance (σ2) =…
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A: Given Data: X~ Normal (12, 4.1) n=45 Let M be the variable of the sample
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A: Null Hypothesis:H0:σ2≤0.04 inches. Alternative Hypothesis: H1:σ2>0.04 inches. Test statistic:…
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A: Population variance is 5.29. The z-critical value for 80% confidence interval is 1.2816 using the…
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Q: A study was conducted to estimate the variance of the annual temperatures of a city. To find this,…
A: Solution: n= 12 Sample size s2=65.4 Sample variance α=0.05 Level of significance
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A: Group 1: Real Magnets n1=22 x1-=4.9 s1=0.96 Group 2 : Fake Magnet n2=21 x2-=5.2 s2=1.4 We have…
Q: Assume thAt scores on a standardized test are known to follow a bell shaped distribution with a mean…
A: L
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A: Given Information : A data set from a study that examined the effect of a specific diet on blood…
Q: If the variance of the Electrical Engineering board examination result is 36, what is the minimum…
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Q: a variance of 65.4 F of the annual temperature was computed. Construct a 95% confidence interval for…
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Q: By what numerical value should SS be divided in order to compute an unbiased variance?
A: The variance is obtained using ratio of squared deviations and sample size.
Q: Step 5 of 5: What is the conclusion?
A: Let be the population variance.Given that,Pop. mean Pop. variance Sample size Sample mean Sample…
Q: estimate of the variance of the population was found to be 15.0 From another sample of 14…
A: Given that n1 = 25 , S12 = 15 , n2 = 14 , S22 = 9.7
Q: If the population variance of the lifetime of a light bulb is 10000 hours, how large of a sample…
A: Given: The population variance of the lifetime of a light bulb is 10000 hours, and a sample must be…
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Q: In order to test the difference in populations means, samples were collected for two independent…
A: Pooled standard deviation:
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A: a) Necessary assumptions for constructing the t-interval are: i) The sample standard deviation are…
Q: A light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs, model A and…
A: The following information has been provided: n1=12 n2=14x¯1=1372…
Q: Mechanical Engineering
A: Where, n is the sample size E is the margin of error σ is the standard deviation
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A: Given: x¯1=110n1=10s12=200x¯2=100n2=15s22=150 Hypothesis: The null and alternative hypotheses are…
Q: A random sample of 10 subjects have weights with a standard deviation of 10.6705 KG. What is the…
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Q: A production engineer wants to determine if two assembly lines are producing the same mean number of…
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Q: Suppose the number of off springs a female eagle raises during its lifetime has a distribution with…
A: Given information: µ=18 σ2=4 n=45 The total number of off-springs produced by the eagles can be…
Q: A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly…
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Q: For a standardized psychology examination, the scores have a mean of 500 and a variance of 9475. It…
A: From the given information we conduct chi square test for variance.
Q: Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. H0:…
A: Given that Sample Variance 1 (s_1^2)(s12) = 10.710.7 Sample Size 1 (n_1)(n1) = 1515 Sample…
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Q: A basketball coach believes that the variance of the heights of adult male basketball players is…
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A: Confidence interval are used to measure the true parameter range under the confidence significance…
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Q: An article about “Relative Controllability of Dissimilar Cars” reported a study in which 14 subjects…
A: sample mean, x = 1.21 sample variance = 160.7824 sample standard deviation, s = 160.7824 = 12.68…
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- The amount of chlorine in 100 cm3 water taken from a water tank was measured, the average was 2.15 mg was found. The expert claims that the amount of chlorine in the water is greater than that measured. For this reason, 100 households were randomly selected, with an average chlorine content of 2.55mg and a variance of 0.49 mg. According to this data, find the account value z. 13 - O A) 8,15 O B) 5,71 O C) -5,71 O D) -8, 15 O E) 0.54The results of a state mathematics test for random samples of students taught by two different teachers at the same school are shown below. Can you conclude there is a difference in the mean mathematics test scores for the students of the two teachers? Use α = 0.01. In addition, assume the populations are normally distributed and the population variances/standard deviations are not equal. Teacher 1 Teacher 2 ?̅1 = 473 ?̅2 = 459 S1 = 39.7 S2 = 24.5 n 1 = 8 n 2 = 18 a. State the null and alternate hypotheses (write it mathematically) and write your claim. b. Find the test statistic c. Identify the Rejection region (critical region) and fail to reject region. Show this by drawing a curve and…Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 7.6 parts/million (ppm). A researcher believes that the current ozone level is not at a normal level. The mean of 1313 samples is 7.2 ppm with a variance of 0.49 Assume the population is normally distributed. A level of significance of 0.02 will be used. Make the decision to reject or fail to reject the null hypothesis.
- The data from an independent-measures research study produce a sample mean difference of 4 points, and each sample has a variance of 10. If there are n = 20 scores in each sample, then what is the estimated standard error of the difference between means?Records from previous years for a casualty insurance company show that its clients average a combined total of 1.9 auto accidents per day, with a variance of 0.31. The actuaries of the company claim that the current variance, oʻ, of the number of accidents per day is not equal to 0.31. A random sample of 17 recent days had a mean of 2 accidents per day with a variance of 0.62. If we assume that the number of accidents per day is approximately normally distributed, is there sufficient evidence to conclude, at the 0.05 level of significance, that the actuaries are correct? 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 below. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the alternative hypothesis H,. p H, :0 H, :0 (b) Determine the type of test statistic to use. (Choose one) ▼ D=0 OSO O20 (c) Find the value of the test statistic. (Round…A drug which is used for treating diabetes has potentially dangerous side effects if it is taken in doses which are larger than the required dosage for the treatment. A medical researcher believes that the variance in dosage is different for two tablets made by different production facilities. The sample variance of a sample of 11 dosages of tablet "A" is 0.013 . The sample variance of a sample of 28 dosages of tablet "B" is 0.01 . Construct the 90% confidence interval for the ratio of the population variances. Round your answers to four decimal places.
- The electric cooperative needs to know the mean household usage of electricity by its non-commercial customers in kWh per day. They would like the estimate to have a maximum error of 0.14 kWh. A previous study found that for an average family the variance is 4.84 kWh and the mean is 19.1 kWh per day. If they are using a 80% level of confidence, how large of a sample is required to estimate the mean usage of electricity? Question 8 options: 45 households 1959 households 949 housholds 405 householdsA certain producer of chocolate has some problems with the variability of five suppliers of cocoa. Since the cocoa quality is critical to the final chocolate product, the company has decided to perform a DOE to compare these suppliers. According to experiences with customers, the capacity of detection of any variation is 3.5 units. Estimate the sample size needed to get at least a power of 85%, given that the historical variance of the process is 2.5 units.If the variance of Aeronautical Engineering board examination results is 144, what is the minimum number if takers needed to estimate the population mean with 95% confidence using a margin of error of 0.80.
- A researcher decides to measure anxiety in group of bullies and a group of bystanders using a 23-item, 3 point anxiety scale. Assume scores on the anxiety scales are normally distributed and the variance among the group of bullies and bystanders are the same. A group of 30 bullies scores an average of 21.5 with a sample standard deviation of 10 on the anxiety scale. A group of 27 bystanders scored an average of 25.8 with a sample standard deviation of 8 on the anxiety scale. You do not have any presupposed assumptions whether bullies or bystanders will be more anxious so you formulate the null and alternative hypothesis based on that.The average size of a farm in Pekan I is 185 acres. The average size of a farm in Pekan II is 100 acre. Assume that the data were obtained from two samples with standard deviations of 38 acres and 12 acres, and sample size of 8 and 9 respectively. Can it be concluded at α = 0.05 that the average size of the farms in Pekan I and Pekan II are different? (Assume equal variances)A researcher wants to measure average cardiovascular health of university students and compare those scores to the average scores in the general population. Assuming that population variance is known, what statistical test is most appropriate for this study? independent-samples t-test single-sample t-test z-test for sample mean related-samples t-test
