Question

In: Statistics and Probability

As part of a water quality​ survey, you test the water hardness in several randomly selected...

As part of a water quality​ survey, you test the water hardness in several randomly selected streams. The results are shown below. Construct a confidence interval for the population variance sigma squared and the population standard deviation sigma. Use a 99 % level of confidence. Assume that the population has a normal distribution.
nequals24
sequals16 grains per gallon

Solutions

Expert Solution

Refer chi-square table or use excel formula "=CHISQ.INV.RT(0.995,23)" & "=CHISQ.INV.RT(0.005,23)" to find the critical values.

---------------------------------------------------------------------------------------------------------


Related Solutions

Describe hardness in water and its effect on water quality with you own words. (2 pages)
Describe hardness in water and its effect on water quality with you own words. (2 pages)
In the survey on the quality of coffee A carried out among 90 randomly selected customers...
In the survey on the quality of coffee A carried out among 90 randomly selected customers of the company dealing with its distribution, the following ratings were obtained: Rating 1 2 3 4 5 6 7 8 9 Number of people 2 4 4 10 17 18 21 8 6 a) Based on the above data, the hypothesis was verified that 40% of all customers put coffee higher than '6' with the alternative that less than 40% giving such a...
In 2015 as part of the General Social Survey, 1220 randomly selected American adults responded to...
In 2015 as part of the General Social Survey, 1220 randomly selected American adults responded to this question: “Some countries are doing more to protect the environment than other countries. In general, do you think that America is doing more than enough, about the right amount, or too little?” Of the respondents, 492 replied that America is doing about the right amount. What is the 95% confidence interval for the proportion of all American adults who feel that America is...
Calculate the test statistic F to test the claim that  = . Two samples are randomly selected...
Calculate the test statistic F to test the claim that  = . Two samples are randomly selected from populations that are normal. The sample statistics are given below. n1 = 25 n2 = 30 = 7.942  = 4.95
2.   A survey of 200 students is selected randomly on a large university campus. They are...
2.   A survey of 200 students is selected randomly on a large university campus. They are asked if they use a laptop in class to take notes. The result of the survey is that 128 of the 200 students responded ”yes." A.   Find 98% confidence interval B.   How would the confidence interval change if the confidence level had been 90% instead of 98%? C.   How would the confidence interval change if the sample size had been 300 instead of 200?...
A survey of 200 students is selected randomly on a large university campus They are asked...
A survey of 200 students is selected randomly on a large university campus They are asked if they use a laptop in class to take notes. The result of the survey is that 70 of the 200 students use laptops to take notes in class. What is the value of the sample proportion? (0.5 pts) What is the standard error of the sampling proportion? (0.5 pts) Construct an approximate 95% confidence interval for the true proportion by going 2 standard...
In a telephone survey completed in the Spring of 2014, a randomly selected number of USadults...
In a telephone survey completed in the Spring of 2014, a randomly selected number of USadults were asked the question “Is there solid evidence that the earth has been warming?”They were also asked their political party preference. The following is a partial summary of the results. What is the sample proportion for adults who prefer the Republican party who wouldanswer “Yes” to the question? What is the approximate standard error for the sampling distribution of sample proportions for this group...
A survey of 150 students is selected randomly on a large university campus. They are asked...
A survey of 150 students is selected randomly on a large university campus. They are asked if they use a laptop in class to take notes. The result of the survey is that 60 of the 150 students responded​ "yes." An approximate 98​% confidence interval is ​(0.307​, 0.493​). Complete parts a through d below. ​b) How would the confidence interval change if the sample size had been 375 instead of 150​? ​(Assume the same sample​ proportion.) The new confidence interval...
A survey of 200 students is selected randomly on a large university campus. They are asked...
A survey of 200 students is selected randomly on a large university campus. They are asked if they use a laptop in class to take notes. Suppose that based on the​ survey, 80 of the 200 students responded​ "yes." ​a) What is the value of the sample proportion ModifyingAbove p with caret​? ​b) What is the standard error of the sample​ proportion? ​c) Construct an approximate 95​% confidence interval for the true proportion p by taking plus or minus 2...
According to a​ survey, the probability that a randomly selected worker primarily drives a car to...
According to a​ survey, the probability that a randomly selected worker primarily drives a car to work is 0.896. The probability that a randomly selected worker primarily takes public transportation to work is 0.033. Complete parts​ (a) through​ (d). (a) What is the probability that a randomly selected worker primarily drives a car or takes public transportation to​ work? ​P(worker drives a car or takes public transportation to ​work)equals nothing ​(Type an integer or decimal rounded to three decimal places...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT