Last year the records of Dairy Land Inc., statistics homework help

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Last year the records of Dairy Land Inc., statistics homework help

BUSINESS STATISTICS

  1. Last year the records of Dairy Land Inc., a convenience store chain, showed the mean amount spent by a customers was $30. A sample of 40 transactions this month revealed the mean amount spent was $33 with a standard deviation of $12. At the 0.05 significance level, can we conclude that the mean amount spent has increased? What is the p-value? Follow and SHOW the five-step hypothesis testing procedure.
  1. The mean construction time for a standard two-car garage by Arrowhead Construction Company is 3.5 days. The time for the construction process follows the normal distribution. The construction process is modified through the use of “precut and assembled roof trusses” rather than onsite construction of roof rafters. This should shorten the construction time. A sample of 15 garages had a mean time of 3.40 days with a standard deviation of 0.8 days. Does use of the “precut and assembled roof trusses” decrease the construction time? Follow the five-step hypothesis testing procedure using the 0.05 significance level.
  1. A typical college student spends an average of 2.55 hours a day using a computer. A sample of 13 students at The University of Findlay revealed the following number of hours per day using the computer:

3.15 3.25 2.00 2.50 2.65 2.75 2.35 2.85 2.95 2.45 1.95 2.35 3.75

Can we conclude that the mean number of hours per day using the computer by students at The University of Findlay is the same as the typical student’s usage? Use the hypothesis testing procedure and the 0.05 significance level.

Business Statistics

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  1. The county commissioners received a number of complaints from county residents that the Youngsville Fire Department takes longer to respond to emergency runs than the Claredon Fire Department. To check the validity of these complaints, a random sample of 60 emergency runs handled by the Youngsville Fire Department was selected. It was found that the mean response time was 6.9 minutes and the standard deviation of the sample is 3.8 minutes. A sample of 70 emergency runs handled by the Claredon Fire Department found the mean response time was 4.9 minutes with a sample standard deviation of 3.0 minutes. Does the data suggest that it takes longer for the Youngsville Department to respond? Use the 0.05 significance level. Show all your work.
  1. A recent study was designed to compare smoking habits of young women with those of young men. A random sample of 150 women revealed that 45 smoked. A random sample of 100 men indicated that 25 smoked. At the 0.05 significance level does the evidence show that a higher proportion of women smoke? Compute the p-value. Show all your work.
  1. A large department store hired a researcher to compare the average purchase amounts for the downtown store with that of its mall store. The information shown below was obtained.

Downtown Store Mall Store

Average Purchase amount $36.00 $40.00

Sample Standard Deviation $10.00 $12.00

Sample Size 10 10

At the 0.01 significance level can it be concluded that the mean amount spent at the mall store is larger? Estimate the p-value and show all your work.

Business Statistics

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  1. A major oil company is studying the relationship between the daily traffic count and the number of gallons of gasoline pumped at company stations. A sample of eight company owned stations is selected and the following information is obtained:

TOTAL GALLONS TRAFFIC COUNT

OF GAS PUMPED OF VEHICLES

LOCATION (000) (000)

West Street 120 4

Willow Street 180 6

Mallard Road 140 5

Pheasant Road 150 5

I-75 210 8

Kinsey Road 100 3

College Street 90 3

Indiana Avenue 80 2

  1. Develop a scatter diagram with the amount of gasoline pumped as the dependent variable.
  2. Compute the coefficient of correlation.
  3. Computer the coefficient of determination.
  4. Interpret the meaning of the coefficient of determination.
  5. Test to determine whether the correlation in the populations is zero, versus the alternate hypothesis that the correlation is greater than zero. Use the 0.05 significance level.
  6. Compute the regression equation.
  7. Compute the standard error of estimate.
  8. Develop a 95 percent confidence interval for the mean amount of gasoline pumped for all stations where the traffic count is 4.
  9. Develop a 95 percent prediction interval for the amount of gasoline pumped at the station at Dowling Road and I-60, which has a count of 4 (actually 400 cars).