FOR NJOSH ONLY

Report of The Car’s Survey

The United States is a country on wheels. Cars are necessary for everyone who lives in America, whether students or workers. With times passing by, most of the college students have their own cars. Lately, we read a piece of news from the Internet about USA Auto Sales Brand Rankings. We can tell that most Americans prefer American cars. Our group would like to confirm whether this news is right or not with TCC’s students being the respondents. So we make an assumption that students in TCC are driving American cars. We selected 30 students in TCC as the sample, collecting information and calculating data we got. Here is what we did about the assumption.

American cars: 44.0%

Japanese cars: 39.1%

Korean cars : 7.9%

Germany cars: 6.0%

Others : 3.0%

This is the sample of the questionnaire survey.

Age: ____ years old.

Male / Female

Nationality: ____________

What is the brand of your car? ___________

What type of car do you have?

1. Sedan

1. SUV

1. Truck

1. Van

1. Other: ____________

How do you know about this car?

1. Friends

1. Family

1. Advertisement

1. Commercial

1. Other: _____________

How long have you owned your car?

How satisfy do you personally think about your car?

When you considering buying a car, what things you generally consider?

a. Vehicle Type Price

b. Brand/ Vehicle Reliability

c. energy-efficient

d. Other: _____________

What’s your car’s gas mileage?

We used the convenience sampling method for our survey because we interview people who have cars and most of them are our friends. If we were to conduct the survey again, we would use the simple random sampling method and survey more people with enough time.

*Note: 3 data in “more than 26” class are 49, 49 and 54. So the midpoint we decided to use is the midpoint of 3 data--51.5, founded by (49+54)/2.

Mean: 22 (21.86667)

Mode: 21 (20-22)

Median: 21

Standard deviation: 2.50

*Note: 2 data in “more than 5 years” class are 5 and 7, so the midpoint we decided to use is the midpoint of 2 data--6.

Mean: 2.33

Mode: 1.5(1-2)

Median: 1.5

Standard deviation: 1.56

Confident interval: 1.85-2.81 (We use 90% as the confidence interval).

We can be reasonably sure (90% confident) that the age of vehicle is between 1.85 and 2.81 years. The best value of mean is 2.33.

Mean: 23.67

Mode: 22.5 (20-25)

Median: 22.5 (20-25)

Standard deviation: 5.83

Confident interval: 21.86--25.46 (We use 90% as the confidence interval)

We can be reasonably sure (90% confident) that the mean gas mileage is between 21.86 and 25.46 mpg. The best value of mean is 23.67.

According to USA Auto Sales Brand Rankings, 44.0% of people living in the country use cars made in American. We want to test whether the cars students in TCC use differs from cars people in the country use.

Null hypothesis Ho µ=44%

Alternate hypothesis H1 µ≠44%

The level of significance we choose is 0.05

Since we know the population proportion we use formula Z= (P-π)/√π (1-π)/n

Z= (P-π)/√π (1-π)/n= (20%-44%)/(√44%(1-44%)/30)=2.65

The critical value is 1.96. We reject the null hypothesis because Z=2.65>1.96.The value of the test statistic lies to the right of 1.96. So we can say the cars that students in TCC use differs from cars people in the country use.

IHS provides information that average age of light vehicle on U.S. roads stayed at 11.4 in 2013. We claim that the average age of cars in TCC is not equal to 11.4.

Null hypothesis Ho µ=11.4

Alternate hypothesis H1 µ≠11.4

The level of significance we choose is 0.05.

Since we don’t know the population standard deviation, the test statistic is the t distribution

t===31.845

The critical value is 2.045. We reject the null hypothesis because t=31.845>2.045.The value of the test statistic lies to the right of critical value. So we can say the cars that the average age of cars in TCC is not equal to average age of light vehicle on U.S. roads

We wonder if there’s correlation between the age of the interviewer and how long they have owned their cars.

r=sxsy =.35

It means there is a direct relationship between the variables. Older people own cars for longer time.

The coefficient of determination is .1225, founded by r2=.352=.1225.

According to the data, we can construct the regression line between the age of the interviewer and how long they have owned their cars.

The independent variable is the age of the interviewer.

The dependent variable is the age of the car.

Using Excel, we get the slope b=.061 and the intercept a=.35.

ŷ= a+bx =.35+.61x

According to USA Auto Sales Brand Rankings,

We wonder if the result is consistent with the information from the website. Use the .05 significance level.

Ho: There’s no difference between TCC’s and national experience for car types.

H1: There’s a difference between TCC’s and national experience for car types.

The critical value is 42.557. We accept the null hypothesis because x2=23.1026＜42.557. The computed value of x2 lies to the left of 43.557. We conclude that the survey results do not provide evidence of a difference between TCC’s and national experience for car types.

According to our survey, we can draw the conclusion—Students in TCC prefer cars made in Japan instead of cars in America. There are some reasons why they choose Japanese cars. First, as most of people we interviewed are our friends, they are international students who cannot work off campus. Price is what they consider first. Second, fuel Efficient is the biggest advantage of Japanese cars. They are fuel efficient and one can save even after buying a car at a very low cost. The advancement of auto technology has helped Japanese car manufactures to produce more fuel efficient cars. Japan is also producing hybrid cars which are more fuel efficient than conventional cars. Another reason is that the quality of these cars is very high. Overall condition is also immaculate. This is because of strict quality tests of Japanese government. If a vehicle does not pass this quality test, it is banned and not allowed to go on the road. Also once the car is sold either through the auction or through any dealer a final inspection of the car is also done.

Work Cited

"GOOD CAR BAD CAR." USA Auto Sales Brand Rankings. Ed. Cain Timothy. N.p., n.d. Web. 16 Mar. 2015.