Question

0 A personnel director in a particular state claims that the mean annual income is the same in one of the state's counties (County A) as it is in another county (County B). In County A, a random sample of 17 residents has a mean annual income of $41,200 and a standard deviation of $8400. In County B, a random sample of 14 residents has a mean annual income of $39,000 and a standard deviation of $5900. At a = 0.05, answer parts (a) through (e). Assume the population variances are not equal. Assume the samples are random and independent, and the populations are normally distributed (a) Identify the claim and state Ho and H Which is the correct claim below? O A. "The mean annual incomes in Counties A and B are not equal." B. "The mean annual incomes in Counties A and B are equal." OC. "The mean annual income in County Ais greater than in County B." OD. "The mean annual income in County A is less than in County B." What are Ho and HA? . Click to select your answer(s). ?

Answer 1

b)

deg of freedom='min(n1,n2)-1=

13

for 0.05 level ,two tail test &13 df, critical t=

-2.160, 2.160

from excel: t.inv(0.975,13)

option B: t <-to ; t>to

c)

Point estimate =x1-x2=		2200.000
std error =√(S21/n1+S22/n2)=		2576.2408
test stat t =(x1-x2-Δo)/Se =		0.854

d)

fail to reject the null hypothesis

e)

we do not have enough evidence,,,,,,,,