A teacher claims that students in a private school have the same exam score that those in public schools. Random samples of 40 students from each type of school are selected and given an exam. The results are given below.

private school public school

x bar =90 x bar =88

s1=12 s2= 10

n1=40 n2=40

A. Find the 95%confidence interval for the difference between the two means.

1.[-2.07, 6.08]

2.[-2.84, 6.84]

3.[-4.37, 8.37]

4.[-2.0, 6.0]

B. At = 0.05, test the teacher's claim.

a) State the hypotheses and identify the claim with the correct hypothesis.

1.

H₀:₁=₂

H₁:_{1 2}(claim)

2.

H₀:₁=₂(claim)

H₁:₁₂

3.

H₀:₁=₂

H₁:₁> ₂(claim)

4.

H₀:₁=₂

H₁:₁< ₂(claim)

b) Find the critical value (s).

1. CV=1.96

2. CV=1.96

3. CV= 2.33

4. CV= -1.65

c) Compute the test value:

1. TV= -1.05

2. TV=0.643

3. TV= 0.81

4. TV= -0.81

d) Make the decision.

1. Reject the null hypothesis.

2.Do not reject the null hypothesis.

e) Summarize the results.

1. There is enough evidence to support the claim.

2.There is not enough evidence to support the claim.