--%>
Assignment Help - homework help

What is your conclusion

The following data were collected on the number of emergency ambulance calls for an urban county and a rural county in Florida. Is County type independent of the day of the week in receiving the emergency ambulance calls? Use α = 0.005. What is your conclusion?

Day of the Week

Sun Mon Tue Wed Thu Fri Sat

County

Urban 62 47 48 51 61 74 41

Rural 6 10 18 17 11 13 12

E

Expert

Verified

Chi square test for independence is applied to test the independence of county from day of the weak.

 

Hypothesis Formation

H0: County is independent from day of the week.

H1: County is Not independent from day of the week.

Test Statistic

Χ2 = ∑(O – E)2/E

Expected Frequency table

Using the below formula, Expected frequencies for relevant columns and rows are calculated. 

Erc = nr*nc/n, where nr is total observed frequency in column c, nc is the total observed frequency in row r where n is total sample size.

 

       Sun        Mon        Tues       Wed       Thurs     Friday   Saturday

Urban  55.4       46.5       53.8       55.4       58.7       70.9       43.2   

Rural  12.6       10.5       12.2       12.6       13.3       16.1       9.79 

 

Critical value of χ2

d.f = (2-1)*(7-1)

      = 6

Upper Critical value χ2 with d.f=6 at significance level of 0.005 = 18.6

Lower Critical value χ2 with d.f=6 at significance level of 0.005 = 0.676

Critical Region

Reject null hypothesis if χ2 is greater than upper critical value of 18.6 or if less than lower critical value of 0.676.

Computation

χ2 = (62-55.4)2/55.4 + (47-46.5)2/46.5 + (48-53.8)2/53.8 + (51-55.4)2/55.4 + (61-58.7)2/58.7 + (74-70.9)2/70.9 + (41-43.2)2/43.2 + (6-12.6)2/12.6 + (10-10.5)2/10.5 + (18-12.2)2/12.2 + (17-12.6)2/12.6 + (11-13.3)2/13.3 + (13-16.1)2/16.1 + (12-9.79)2/9.79

= 11.4

Decision

As χ2 is neither less than 0.676 nor greater than 18.6, so we can’t reject null hypothesis. Therefore county is independent from day of the week.

 

   Related Questions in Basic Statistics

  • Q : Sample z test and Sample t test A

    A random sample X1, X2, …, Xn is from a normal population with mean µ and variance σ2. If σ is unknown, give a 95% confidence interval of the population mean, and interpret it. Discuss the major diff

    		•
  • Q : Explain Service times Service times: A)

    Service times:A) In most cases, servicing a request takes a “short” time, but in a few occasions requests take much longer.B) The probability of completing a service request by time t, is independent of how much tim

    		•
  • Q : STATISTICS Question This week you will

    This week you will analyze if women drink more sodas than men.  For the purposes of this Question, assume that in the past there has been no difference.  However, you have seen lots of women drinking sodas the past few months.  You will perform a hypothesis test to determine if women now drink more

    		•
  • Q : Define Operational Analysis

    Operational Analysis: • Analysis method based on the measurement of the operational characteristics of the system.

    Q : Program Evaluation and Review

    Program Evaluation and Review Technique (PERT) A) Developed by US Navy and a consulting firm in 1958 for the Polaris submarine project. B) Technique as for CPM method, but acti

    		•
  • Q : Explain Service times Service times: A)

    Service times:A) In most cases, servicing a request takes a “short” time, but in a few occasions requests take much longer.B) The probability of completing a service request by time t, is independent of how much tim

    		•
  • Q : Creating Grouped Frequency Distribution

    Creating Grouped Frequency Distribution: A) At first we have to determine the biggest and smallest values. B) Then we have to Calculate the Range = Maximum - Minimum C) Choose the number of classes wished for. This is generally between 5 to 20. D) Find out the class width by dividing the range b

    		•
  • Q : Model Checking Approach Model Checking

    Model Checking Approach: • Specify program model and exhaustively evaluate that model against a speci?cation        –Check that properties hold   

  • Q : Regression Analysis 1. A planning

    1. A planning official in the Texas Department of Community Affairs, which works in the office next to you, has a problem. He has been handed a data set from his boss that includes the costs involved in developing local land use plans for communities wi

    		•
  • Q : State the hypotheses At Western

    At Western University the historical mean of scholarship examination score for freshman applications is 900. Population standard deviation is assumed to be known as 180. Each year, the assistant dean uses a sample of applications to determine whether the mean ex

    		•