Question

Many people claimed that the average cost of living for grocery expenses for family with one or two children in the Washington D.C metropolitan is exceeded $1,200 per month. In a sample of 100 family survey undertaken in the Washington D.C metropolitan area in July 2019. The average cost and standard deviation of living for grocery expenses for family with one or two children in the Washington D.C metropolitan are found to be $1,380 and $190, respectively. Do these data support the claim that the cost for living is exceeded $1,200 per month? Using alpha equals 0.05, the test statistic is:

a. 8.725

b. -9.474

c. 9.874

d. -1.645

e. 9.474

Second part is:
Refer to question 5. At alpha equals 0.05, we:

    a.  
reject the null since Z-statistic is less than Z of alpha

    b.  
reject the null since Z-statistic not equal to Z of alpha

    c.  
reject the null since Z-statistic is more than Z of alpha

    d.  
fail to the reject the null since Z-statistics is less than Z of alpha

    e.  
fail to reject the null since Z-statistic is more than Z of alpha

Answer 1

H0: 1200

Ha: > 1200

Test statistics

z = ( - ) / ( / sqrt(n) )

= ( 1380 - 1200) / ( 190 / sqrt(100) )

= 9.474

Critical value Z = 1.645 (from Z table)

Decision = reject the null since Z-statistic is more than Z of alpha