Statistics hw help!! BEST ANSWER 10 points please help?

1.

For a one-tailed, alpha = 0.01 , you are looking for P(z<Z) = 0.99

z(2.32) = 0.98983

z(2.33) = 0.99010

If you interpolate, it is about z(2.326347874) = 0.99

You can round to 2.326 for test purposes

The critical value is between 2.32 and 2.33

so 2.43 is greater than 2.326 so he can reject the NULL Hypothesis

For a two-tailed test,

You have two 0.005 tails which adds up to 2*0.005 = 0.10, so you look P(z<Z)= 0.995

z(2.57) = .99492

z(2.58) = .99506

Interpolating gives about z=2.576. for P(z<Z )= 0.995

2.43 is less than 2.576 , so you cannot reject the NULL Hypothesis for a two-tailed test.

Interpolating gives about z=2.576.

2. alpha = 0.01 One tailed since the question that his class is better, not just difference.

a.

Z = (x- mean) / (std_dev/ sqrt(N) ) = (102-100)/ (11/sqrt(100)) = 2 /( 11/10) = 2/1.1

Z = 1.818181818

Z (one-tailed for 0.01) = about 2.326 (from above)

since 1.81818 is less than 2.326, you cannot reject the NULL Hypothesis and his claim is not proven correct.

b. alpha -= 0.05

test is still Z = 1.81818

P(z<1.64) = .94950

P(z<1.65) = .95053

Since it is about halfway between the two value, you can use 1.645.

Critical Z is now P(z<Z) = 0.95 give z= approx. 1.645

Since 1.81818 is greater than 1.645 , you can reject the NULL Hypothesis and he claim is correct.

Nsat Test