The hydrocarbon emissions at idling speed in parts per million (ppm) for automobiles of 1980 and...

The hydrocarbon emissions at idling speed in parts per million (ppm) for automobiles of 1980 and 1990 model years are given for 20 randomly and independently selected cars. The data can be found in the excel file Auto with variables name Model and Emission. At the 5% significance level, do we have sufficient evidence to conclude that the true mean hydrocarbon emissions were greater for 1980 models than 1990 models? (17 points total)

Label the Parameters: (3 points)
State null and alternative hypotheses in parameter notation: (2 points)

H₀:

H_a:

Propose an appropriate hypothesis test. Explain! (2 points)
Verify the required conditions for the proposed hypothesis test: (3 points)

Randomization assumption:

Normality assumption:

Equal population variance assumption:

Note: Attach R codes and outputs in the following space:

Report a test statistic, df, and p-value. (3 points)

Test statistic =

df =

p-value =

Note: Attach R codes and outputs in the following space:

Make a decision of hypothesis test: (2 points)

Make a conclusion of hypothesis test in context: (2 points)

Model	Emission
Eighty	380
Eighty	475
Eighty	241
Eighty	340
Eighty	435
Eighty	210
Eighty	300
Eighty	306
Eighty	210
Eighty	450
Eighty	241
Eighty	590
Eighty	542
Eighty	440
Eighty	225
Eighty	247
Eighty	223
Eighty	359
Eighty	280
Eighty	141
Ninety	210
Ninety	305
Ninety	290
Ninety	286
Ninety	175
Ninety	225
Ninety	200
Ninety	224
Ninety	290
Ninety	210
Ninety	235
Ninety	223
Ninety	176
Ninety	170
Ninety	217
Ninety	170
Ninety	290
Ninety	190
Ninety	220
Ninety	140

Solutions

Expert Solution

orchestra answered 1 year ago

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