Periodically, a town water department tests the drinking water of homeowners for contaminants such as lead. The lead levels in water specimens collected for a sample of 10 residents of the town had a mean 2.9 mg/L and a standard deviation of 2.1 mg/L. Complete parts a through c.
a. Construct a 90% confidence interval for the mean lead level in water specimens from the town.
b. Interpret the interval in terms of this application.
c. what is meant by the phrase "90% confidence interval"?
Periodically, a town water department tests the drinking water of homeowners for contaminants such as lead....
Periodically, a town water department tests the the drinking water of homeowners for contaminants such as lead. The lead levels in water specimens collected for a sample of 10 residents of the town had a mean of 3.4mg/L and a standard deviation of 2.1 mg/L. Complete parts a throughM c. a.Construct a 90% confidence interval for the mean lead level in water specimens from the town. (Round to three decimal places as needed.)
Periodically, a town water department tests the the drinking water of homeowners for contaminants such as lead. The lead levels in water specimens collected for a sample of 10 residents of the town had a mean of 3.2 mg/L and a standard deviation of 2.6 mg/L. Complete parts a throughc. a.Construct a 90% confidence interval for the mean lead level in water specimens from the town.(______,______) (Round to three decimal places as needed.)
Periodically, the county Water Department tests the drinking water of homeowners for contaminants such as lead and copper. The lead and copper levels in water specimens collected in 1998 for a sample of 10 residents of a subdevelopement of the county are shown below. lead (μ g/L) copper (mg/L) 5.8 0.36 2.8 0.825 5.3 0.285 2.7 0.157 0.9 0.339 0.6 0.147 2 0.407 4 0.081 4.7 0.261 4.2 0.762 Round all values to at least four decimal places. (a) Construct...
(1 point) Periodically, the County Water Department tests the drinking water of homeowners for contminants such as lead and copper. The lead and copper levels in water specimens collected for a sample of 10 residents of a subdevelopement of a county are shown below. lead (ug/L) copper (mg/L) 2.3 0.698 0.1 0.564 4.3 0.255 0.5 0.433 3.2 0.682 4.5 0.079 5.1 0.691 5.4 0.028 4.9 0.643 5.7 0.124 (a) Construct a 99% confidence interval for the mean lead level in...
TOTAL MARKS: 25 QUESTION 3 (a) Periodically, the county council tests the drinking water of homeowners for contaminants such as lead. The lead levels in water specimens (ug/L) collected in 2017 for a sample of 12 residents of the county are shown below: 1.6, 3.3, 3.8, 0.7, 0.5, 1.3, 3.8, 4.2, 2.4, 2.9, 0.9, 3.5 (i) Calculate the sample mean and sample standard deviation for these measurements (ii) Construct the 99% confidence interval for the true mean μ using an...
5. An application of the distribution of sample meansPeople suffering from hypertension, heart disease, or kidney problems may need to limit their intakes of sodium. The public health departments in some U.S. states and Canadian provinces require community water systems to notify their customers if the sodium concentration in the drinking water exceeds a designated limit. In Connecticut, for example, the notification level is 28 mg/L (milligrams per liter).Suppose that over the course of a particular year the mean concentration...
The Environmental Protection Agency (EPA) is concerned about the amount of chloride in household water supplies. In a sample of 18 households, the amounts (in mg/L) of chloride was recorded, as follows: 16 0 0 2 3 6 8 2 5 0 12 10 5 7 2 8 6 9 (a) Calculate the mean, standard deviation and standard error of the mean for the above data. (b) Construct and interpret a 98% confidence interval for the true mean amount of...
2) A study done in 2016 showed that 38% of drivers admitted to text messaging while driving. A researcher decides to conduct another study to see if things have changed since then. The researcher wants the new study to have no more than a confidence level of 95%. results? 4% error with a How many responses does the researcher need to achieve these b) There is not enough evidence to reject the claim d) There is not enough evidence to...
explaim the mechanisms amd toxological effects if type 1 diabetes in this article Exposure to arsenic in drinking water is associated with increased prevalence of diabetes. We previously reported an association of diabetes and urinary concentration of dimethylarsinite (DMAS"), a toxic product of arsenic methylation by arsenic (+ 3 oxidation state) methyltransferase (AS3MT). Here we examine associations between AS3MT polymorphism, arsenic metabolism and diabetes. Fasting blood glucose, oral glucose tolerance and self-reported diagnoses were used to identify diabetic individuals. Inorganic...