this is part two. I got the answer wrong and i trying to figure out the answers before this test. Let x be a random variable that represents micrograms of lead per liter of water (µg/L). An industrial plant discharges water into a creek. The Environmental Protection Agency (EPA) has studied the discharged water and found x to have a normal distribution, with σ = 0.7 µg/L. † Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value a small amount and thereby produce a slightly more "conservative" answer. (a) The industrial plant says that the population mean value of x is μ = 2.0 µg/L. However, a random sample of n = 10 water samples showed that x = 2.54 µg/L. Does this indicate that the lead concentration population mean is higher than the industrial plant claims? Use a = 1% (i) the level of significance which is 0.01 and the value of the sample test statistic is 2.44 (iii)p-value<0.010     (iv) Based on your answers in parts (i) to (iii), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level α? At the α = 0.01 level, we fail to reject the null hypothesis and conclude the data are statistically significant.At the α = 0.01 level, we reject the null hypothesis and conclude the data are statistically significant.     At the α = 0.01 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.At the α = 0.01 level, we reject the null hypothesis and conclude the data are not statistically significant.     (b) Find a 95% confidence interval for μ using the sample data and the EPA value for σ. (Round your answers to two decimal places.) lower limit upper limit(c) How large a sample should be taken to be 95% confident that the sample mean x is within a margin of error E = 0.4 µg/L of the population mean? (Round your answer up to the nearest whole number.)      ?  water samples

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.4: Distributions Of Data
Problem 22PFA
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this is part two. I got the answer wrong and i trying to figure out the answers before this test.

Let x be a random variable that represents micrograms of lead per liter of water (µg/L). An industrial plant discharges water into a creek. The Environmental Protection Agency (EPA) has studied the discharged water and found x to have a normal distribution, with

σ = 0.7 µg/L.

Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value a small amount and thereby produce a slightly more "conservative" answer.

(a) The industrial plant says that the population mean value of x is
μ = 2.0 µg/L.
However, a random sample of
n = 10
water samples showed that
x = 2.54 µg/L.
Does this indicate that the lead concentration population mean is higher than the industrial plant claims? Use
a = 1%
(i) the level of significance which is 0.01
and the value of the sample test statistic is 2.44
(iii)p-value<0.010
 
 
(iv) Based on your answers in parts (i) to (iii), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level α?
At the α = 0.01 level, we fail to reject the null hypothesis and conclude the data are statistically significant.At the α = 0.01 level, we reject the null hypothesis and conclude the data are statistically significant.     At the α = 0.01 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.At the α = 0.01 level, we reject the null hypothesis and conclude the data are not statistically significant.
 
 
(b) Find a 95% confidence interval for μ using the sample data and the EPA value for σ. (Round your answers to two decimal places.)
lower limit
upper limit

(c) How large a sample should be taken to be 95% confident that the sample mean
x
is within a margin of error
E = 0.4 µg/L
of the population mean? (Round your answer up to the nearest whole number.)
     ?  water samples
 
 
 
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