Auto emissions Oxides of nitrogen (called NOX for short) emitted by cars and trucks are

Chapter 8, Problem 6

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QUESTION:

Auto emissions Oxides of nitrogen (called NOX for short) emitted by cars and trucks are important contributors to air pollution. The amount of NOX emitted by a particular model varies from vehicle to vehicle. For one light-truck model, NOX emissions vary with mean \(\mu=1.8\) grams per mile and standard deviation \(\sigma=0.4\) gram per mile. You test an SRS of 50 of these trucks. The sample mean NOX level \(\bar{x}\) will vary if you take repeated samples.

(a) Describe the shape, center, and spread of the sampling distribution of \(\bar{x}\)

(b) Sketch the sampling distribution of \(\bar{x}\) Mark its mean and the values 1, 2, and 3 standard deviations on either side of the mean.


(c) According to the 68-95-99.7 rule, about 95% of all values of \(\bar{x}\) lie within a distance
m of the mean of the sampling distribution. What is m? Shade the region on the axis of your sketch that is within m of the mean.


(d) Whenever \(\bar{x}\) falls in the region you shaded, the unknown population mean \(\mu\) lies in the confidence interval \(\bar{x} \pm m\). For what percent of all possible samples does the interval capture \(\mu\)?

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QUESTION:

Auto emissions Oxides of nitrogen (called NOX for short) emitted by cars and trucks are important contributors to air pollution. The amount of NOX emitted by a particular model varies from vehicle to vehicle. For one light-truck model, NOX emissions vary with mean \(\mu=1.8\) grams per mile and standard deviation \(\sigma=0.4\) gram per mile. You test an SRS of 50 of these trucks. The sample mean NOX level \(\bar{x}\) will vary if you take repeated samples.

(a) Describe the shape, center, and spread of the sampling distribution of \(\bar{x}\)

(b) Sketch the sampling distribution of \(\bar{x}\) Mark its mean and the values 1, 2, and 3 standard deviations on either side of the mean.


(c) According to the 68-95-99.7 rule, about 95% of all values of \(\bar{x}\) lie within a distance
m of the mean of the sampling distribution. What is m? Shade the region on the axis of your sketch that is within m of the mean.


(d) Whenever \(\bar{x}\) falls in the region you shaded, the unknown population mean \(\mu\) lies in the confidence interval \(\bar{x} \pm m\). For what percent of all possible samples does the interval capture \(\mu\)?

ANSWER:

Step 1 of 6

Given,

Sample size,

The NOX emissions mean,

The standard deviation,

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