Question

1- Assume the cholesterol levels in a certain population have mean u- 200 and standard deviation σ 24. The cholesterol levels for a random sample of n individuals are measured and the sample mean x is determined. What is the z-score for a sample mean x - 180? (a) reject the null if the calculated Z> 1.96 (b) reject the null ifthe calculated Z#196 (c) do not reject the null if lcalc zl is <1.96 (d) reject the null if the calculated Z> l19 2- A drink vending machine is adjusted so that, on average, it dispenses 220 mls of fruit juice (with a standard deviation of 10mls) into a plastic cup. However, the machine has a tendency to go out of adjustment and periodic checks are made to determine the average amount of fruit juice actually being dispensed. A sample of 45 drinks is taken to test the adjustment of the machine. For 5%, an appropriate decision rule would be (b) -0.83 (d) 2.50 (a) -3.75 (c) -2.50

Answer 1

1)

If | z | < critical value we do not reject the null hypothesis.

Correct option is (c) do not reject the null if | calc Z | is < 1.96