Statistics

Question 1

P-value

Answer 1

Usually to test if mean has changed
1. Get z of (new mean - old mean) / (ō / root of n)
2. p = 2 X P(> |z|)
3. If p < 0.05, mean has changed reject Ho

Question 2

Ways to test mean hypothesis at 95%

Answer 2

1. Get z score from top of page 35, reject if less than -1.96 or more than 1.96
2. Confidence interval of new mean (add & subtract 1.96XE) reject if old mean outside range
3. Confidence interval of old mean (add & subtract 1.96XE) reject if new mean outside range

Question 3

Find sample size n if error is y%
Not told standard dev

Answer 3

1/root n = 0.y

Question 4

What to remember when writing confidence interval at 95%

Answer 4

1.96 X the error