Researchers are investigating the number of car crashes occurring on a certain stretch of a highway....

Researchers are investigating the number of car crashes occurring on a certain stretch of a highway. They classify the crashes as early in the week (Monday/Tuesday), mid-week (Wednesday/Thursday) or on the weekend (Friday/Saturday/Sunday). The number of crashes for each time period is given in the table below:

Early	Mid-Week	Weekend
28	34	46

Use the appropriate hypothesis test at the 5% level to determine if the proportions of crashes occurring on this stretch of highway are different for the 3 time periods.

Expert Solution

Null hypothesis: Ho: proportions of crashes occurring on this stretch of highway are same for the 3 time periods.

Alternate hypothesis: Ha: the proportions of crashes occurring on this stretch of highway are different for the 3 time periods.

degree of freedom =categories-1=	2
for 0.05 level and 2 df :crtiical value X2 =	5.991	*from excel: chiinv(0.05,2)*
Decision rule: reject Ho if value of test statistic X2>5.991

applying chi square goodness of fit test:

	relative	observed	Expected	Chi square
Category	frequency(p)	O_i	E_i=total*p	R²_i=(O_i-E_i)²/E_i
Early	0.3333	28	36.00	1.78
Mid-Week	0.3333	34	36.00	0.11
Weekend	0.3333	46	36.00	2.78
total	1.00	108	108	4.67

test statistic X²=		4.667

since test statistic does not falls in rejection region we fail to reject null hypothesis

we do not have have sufficient evidence to conclude that the proportions of crashes occurring on this stretch of highway are different for the 3 time periods.

orchestra answered 2 years ago

Assume the speed of vehicles along an open stretch of a certain highway in Texas that...

Assume the speed of vehicles along an open stretch of a certain highway in Texas that is not heavily traveled has an approximately Normal distribution with a mean of 71 mph and a standard deviation of 3.125 mph. The current posted speed limit is 65 mph. What is the proportion of vehicles going above the current posted speed limit? What proportion of the vehicles would be going less than 50 mph? What proportion of the vehicles would be going between...

According to the statistics reported, a surprsing number of car crashes are not covered by insurance....

According to the statistics reported, a surprsing number of car crashes are not covered by insurance. Simple results, consistent with the report, showed 41 of 183 vehicals were not covered by by insurance. Test the hypothesis that the porportion of vehicles not covered by insurance is 17% at .1 level of significance. Find the critical value, test statistic, and the P value Reject of fail to reject the null? then construct a 80% confidence interval for the true proprotion of...

Researchers at an infectious disease clinic interested in investigating the relationship between mortality and a number...

Researchers at an infectious disease clinic interested in investigating the relationship between mortality and a number of comorbidities in their patients that are HIV positive. Researchers hypothesize that early mortality is most strongly associated with heroin use in their patient population. In order to better assess their relationship, the researchers decided to control for a variety of other comorbidities along with age and gender. The following is a representation of their multiple linear regression model (NOTE: the output is a bit...

Assume that the speeds of cars travelling on a stretch of highway are normally distributed. A...

Assume that the speeds of cars travelling on a stretch of highway are normally distributed. A sample of 25 cars on this highway found a mean speed of 70 mph with a standard deviation of 6 mph. Construct a 95% confidence interval for the true mean speed of all cars travelling on this stretch of highway. (need check the assumptions) What is the margin of error in (1). Interpret the 95% confidence interval in the context of the problem.

Suppose you would like to know the average daily number of car crashes that occur at...

Suppose you would like to know the average daily number of car crashes that occur at your hometown. With that in mind, you take a sample of 15 days where you record the number of car crashes at your hometown on each of those days. The data are displayed below: 12, 7, 17, 11, 9, 8, 19, 22, 12, 17, 15, 9, 12, 21, 15 a) Please calculate the sample average. b) Please calculate the standard error of the sample average. (Please make sure to show your calculations.) c) Your friend claims that the population average (mean) for the...

The U.S. National Highway Traffic Safety Administration gathers data concerning the causes of highway crashes where...

The U.S. National Highway Traffic Safety Administration gathers data concerning the causes of highway crashes where at least one fatality has occurred. From the 1998 annual study, the following probabilities were determined (BAC is blood-alcohol level): ?(???=0|Crash with fatality)=0.631P(BAC=0|Crash with fatality)=0.631 ?(??? is between .01 and .09|Crash with fatality)=0.325P(BAC is between .01 and .09|Crash with fatality)=0.325 ?(??? is greater than .09|Crash with fatality)=0.098P(BAC is greater than .09|Crash with fatality)=0.098 Suppose over a certain stretch of highway during a 1-year period,...

Name the four (4) factors involved in highway crashes. Explain or define Grade-Separated highway. Define and...

Name the four (4) factors involved in highway crashes. Explain or define Grade-Separated highway. Define and explain two (2) types of At-Grade Intersections, and use diagrams to illustrate your explanations. How many Right-of-Way (R/W) Categories do we have in Urban Public Transportation modes? Explain in detail the operational and physical characteristics of the R/W Categories identified. Give real world examples for each.

Answer ASAP: Probability and Statistics question On average, 2.4 car accidents occur on certain highway each...

Answer ASAP: Probability and Statistics question On average, 2.4 car accidents occur on certain highway each month (which is assumed to always have 30 days). Answer the following questions: (a) What is the probability of having at least 1 accident on the highway next month? Hint: Let LaTeX: XX denote the number of car accidents on the highway next month. What distribution does LaTeX: X X have? (b) What is the probability that there will be no accident during the...

During a recent 24 hour period, on a particular stretch of freeway, the Highway Patrol issued...

During a recent 24 hour period, on a particular stretch of freeway, the Highway Patrol issued 426 tickets, of which 63 went to drivers of red cars. a.Find a 95% confidence interval for the proportion of tickets went to drivers of red cars. b.Based on the preliminary survey, determine how large a sample size is needed in order to estimate p to within 0.01 with 95% confidence level. c.Use a 5% significant level, a researcher for Red Cars of America...

1-The mean speed of vehicles along a stretch of highway is 75 miles per hour with...

1-The mean speed of vehicles along a stretch of highway is 75 miles per hour with a standard deviation of 3.8 miles per hour. Your current speed along this stretch of highway is 62 miles per hour. What is the z-score for your speed? z- score =_______ (Round to two decimal places) 2- For a statistics test the mean is 63 and the standard deviation is 7.0, and for a biology test the mean is 23 and the standard deviation...

Question