Unfortunately, arsenic occurs naturally in some ground water.t A mean arsenic level of u = 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 tests gave a sample mean of x = 6.7 ppb arsenic, with s = 3.0 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use a = 0.01. A USE SALT (a) What is the level of significance? State the null and alternate hypotheses. O Ho: H = 8 ppb; H,: u> 8 ppb O Ho: H = 8 ppb; H,: u + 8 ppb O Ho: H< 8 ppb; H,: u = 8 ppb O Ho: H> 8 ppb; H,: u = 8 ppb O Ho: H = 8 ppb; H,: u < 8 ppb (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The standard normal, since the sample size is large and a is known. O The Student's t, since the sample size is large and a is known. O The Student's t, since the sample size is large and o is unknown. O The standard normal, since the sample size is large and o is unknown. What is the value of the sample test statistic? (Round your answer to three decimal places.) (c) Estimate the P-value. O P-value > 0.100 O 0.050 < P-value < 0.100 O 0.010 < P-value < 0.050 0.005 < P-value < 0.010 O P-value < 0.005 Sketch the sampling distribution and show the area corresponding to the P-value.
Unfortunately, arsenic occurs naturally in some ground water.t A mean arsenic level of u = 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 tests gave a sample mean of x = 6.7 ppb arsenic, with s = 3.0 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use a = 0.01. A USE SALT (a) What is the level of significance? State the null and alternate hypotheses. O Ho: H = 8 ppb; H,: u> 8 ppb O Ho: H = 8 ppb; H,: u + 8 ppb O Ho: H< 8 ppb; H,: u = 8 ppb O Ho: H> 8 ppb; H,: u = 8 ppb O Ho: H = 8 ppb; H,: u < 8 ppb (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The standard normal, since the sample size is large and a is known. O The Student's t, since the sample size is large and a is known. O The Student's t, since the sample size is large and o is unknown. O The standard normal, since the sample size is large and o is unknown. What is the value of the sample test statistic? (Round your answer to three decimal places.) (c) Estimate the P-value. O P-value > 0.100 O 0.050 < P-value < 0.100 O 0.010 < P-value < 0.050 0.005 < P-value < 0.010 O P-value < 0.005 Sketch the sampling distribution and show the area corresponding to the P-value.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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Transcribed Image Text:Unfortunately, arsenic occurs naturally in some ground water.t A mean arsenic level of u = 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 tests gave a sample mean of x = 6.7 ppb arsenic, with s = 3.0 ppb. Does this information indicate that the mean level of arsenic
in this well is less than 8 ppb? Use a = 0.01.
n USE SALT
(a) What is the level of significance?
State the null and alternate hypotheses.
O Ho: H = 8 ppb; H,: u > 8 ppb
O Ho: H = 8 ppb; H,: H + 8 ppb
O Ho: H < 8 ppb; H,: u = 8 ppb
O Ho: H> 8 ppb; H,: u = 8 ppb
O Ho: H = 8 ppb; H,: µ < 8 ppb
(b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution.
O The standard normal, since the sample size is large and a is known.
The Student's t, since the sample size is large and o is known.
O The Student's t, since the sample size is large and o is unknown.
O The standard normal, since the sample size is large and o is unknown.
What is the value of the sample test statistic? (Round your answer to three decimal places.)
(c) Estimate the P-value.
O P-value > 0.100
O 0.050 < P-value < 0.100
O 0.010 < P-value < 0.050
O 0.005 < P-value < 0.010
P-value < 0.005
Sketch the sampling distribution and show the area corresponding to the P-value.
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