Question 1

NARRBEGIN: Undergraduates' Test Scor
Undergraduates' Test Scores
35 undergraduate students who completed two years of college were asked to take a basic mathematics test. The mean and standard deviation of their scores were 75.1 and 12.8, respectively. In a random sample of 50 students who only completed high school, the mean and standard deviation of the test scores were 72.1 and 14.6, respectively.NARREND
-{Undergraduates' Test Scores Narrative} Explain how to use the interval estimate to test the hypotheses.

Accepted Answer

The answer of NARRBEGIN: Undergraduates' Test Scor
Undergraduates' Test Scores
35 undergraduate...

Question 2

NARRBEGIN: Starting Salary
Starting Salary
In testing the hypotheses $H _ { 0 } : \mu _ { 1 } - \mu _ { 2 } = 0$ vs. $H _ { 1 } : \mu _ { 1 } - \mu _ { 2 } \neq 0$ , two random samples from two populations of college of business graduates majoring in global marketing and international business produced the following statistics regarding their starting salaries (in $1000s): $n _ { 1 } = 50$ , $\bar { x } _ { 1 } = 35$ , $s _ { 1 } = 28$ , $n _ { 2 } = 50$ , $\bar { x } _ { 2 } = 30$ , and $s _ { 2 } = 10$ . (Assume the salaries have normal distributions.)
NARREND
-{Starting Salary Narrative} Explain how to use the 95% confidence interval to test the hypotheses at $\alpha$= .05.

Accepted Answer

The answer of NARRBEGIN: Starting Salary
Starting Salary
In testing the hypotheses...

Question 3

NARRBEGIN: Undergraduates' Test Scor
Undergraduates' Test Scores
35 undergraduate students who completed two years of college were asked to take a basic mathematics test. The mean and standard deviation of their scores were 75.1 and 12.8, respectively. In a random sample of 50 students who only completed high school, the mean and standard deviation of the test scores were 72.1 and 14.6, respectively.NARREND
-{Undergraduates' Test Scores Narrative} Estimate with 90% confidence the difference in mean scores between the two groups of students.

Accepted Answer

The answer of NARRBEGIN: Undergraduates' Test Scor
Undergraduates' Test Scores
35 undergraduate...

Question 4

NARRBEGIN: Additives
Additives
A food processor wants to compare two additives for their effects on retarding spoilage. Suppose 16 cuts of fresh meat are treated with additive A and 16 are treated with additive B, and the number of hours until spoilage begins is recorded for each of the 32 cuts of meat. The results are summarized in the table below
 $$\begin{array} { | l | c | c | } 
\hline & \text { Additive A } & \text { Additive B } \
\hline \text { Sample Mean } & 108.7 \text { hours } & 98.7 \text { hours } \
\hline \text { Sample Standard Deviation } & 10.5 \text { hours } & 13.6 \text { hours } \
\hline
\end{array}$$ NARREND
-{Additives Narrative} Assume population variances are equal. Calculate the pooled variance and the value of the test statistic.

Accepted Answer

The answer of NARRBEGIN: Additives
Additives
A food processor wants to compare...

Question 5

NARRBEGIN: Additives
Additives
A food processor wants to compare two additives for their effects on retarding spoilage. Suppose 16 cuts of fresh meat are treated with additive A and 16 are treated with additive B, and the number of hours until spoilage begins is recorded for each of the 32 cuts of meat. The results are summarized in the table below
 $$\begin{array} { | l | c | c | } 
\hline & \text { Additive A } & \text { Additive B } \
\hline \text { Sample Mean } & 108.7 \text { hours } & 98.7 \text { hours } \
\hline \text { Sample Standard Deviation } & 10.5 \text { hours } & 13.6 \text { hours } \
\hline
\end{array}$$ NARREND
-{Additives Narrative} Determine the rejection region at $\alpha$ = .05 and write the proper conclusion.

Accepted Answer

The answer of NARRBEGIN: Additives
Additives
A food processor wants to compare...

Question 6

NARRBEGIN: Undergraduates' Test Scor
Undergraduates' Test Scores
35 undergraduate students who completed two years of college were asked to take a basic mathematics test. The mean and standard deviation of their scores were 75.1 and 12.8, respectively. In a random sample of 50 students who only completed high school, the mean and standard deviation of the test scores were 72.1 and 14.6, respectively.NARREND
-{Undergraduates' Test Scores Narrative} Can we infer at the 10% significance level that a difference exists between the two groups?

Accepted Answer

The answer of NARRBEGIN: Undergraduates' Test Scor
Undergraduates' Test Scores
35 undergraduate...

Question 7

NARRBEGIN: Additives
Additives
A food processor wants to compare two additives for their effects on retarding spoilage. Suppose 16 cuts of fresh meat are treated with additive A and 16 are treated with additive B, and the number of hours until spoilage begins is recorded for each of the 32 cuts of meat. The results are summarized in the table below
 $$\begin{array} { | l | c | c | } 
\hline & \text { Additive A } & \text { Additive B } \
\hline \text { Sample Mean } & 108.7 \text { hours } & 98.7 \text { hours } \
\hline \text { Sample Standard Deviation } & 10.5 \text { hours } & 13.6 \text { hours } \
\hline
\end{array}$$ NARREND
-{Additives Narrative} State the null and alternative hypotheses to determine if the average number of hours until spoilage begins differs for the additives A and B.

Accepted Answer

The answer of NARRBEGIN: Additives
Additives
A food processor wants to compare...

Question 8

NARRBEGIN: Starting Salary
Starting Salary
In testing the hypotheses $H _ { 0 } : \mu _ { 1 } - \mu _ { 2 } = 0$ vs. $H _ { 1 } : \mu _ { 1 } - \mu _ { 2 } \neq 0$ , two random samples from two populations of college of business graduates majoring in global marketing and international business produced the following statistics regarding their starting salaries (in $1000s): $n _ { 1 } = 50$ , $\bar { x } _ { 1 } = 35$ , $s _ { 1 } = 28$ , $n _ { 2 } = 50$ , $\bar { x } _ { 2 } = 30$ , and $s _ { 2 } = 10$ . (Assume the salaries have normal distributions.)
NARREND
-The service manager of a car dealer wants to determine if owners of new cars (two years old or less) tune up their cars more frequently than owners of older cars (more than two years old). From his records he takes a random sample of ten new cars and ten older cars and determines the number of times the cars were tuned up in the last 12 months. The data follow. Do these data allow the service station owner to infer at the 10% significance level that new car owners tune up their cars more frequently than older car owners?
 $$\begin{array}{l}
\text { Frequency of Tunsups in past 12 Month }\
\begin{array} { |c | c| } 
\hline \text { New Car Owmers } & \text { Old Cars Owners } \
\hline 6 & 4 \
3 & 2 \
3 & 1 \
3 & 2 \
4 & 3 \
3 & 2 \
6 & 2 \
5 & 3 \
5 & 2 \
4 & 1 \
\hline
\end{array}
\end{array}$$

Accepted Answer

The answer of NARRBEGIN: Starting Salary
Starting Salary
In testing the hypotheses...

Quiz 13: Inference About Comparing Two Populations