Question

1. Which distribution will have a smaller standard deviation?

   1. The population distribution

   2. The sampling distribution

2. As the confidence level decreases the value of z for the confidence level gets:

   1. Smaller

   2. Larger

   3. Either smaller or larger but we can’t say which

3. What is the value for z* for an 80% confidence interval for any given mean. Show all work. Round to two decimal places.

4. Blood glucose levels for obese patients have a mean of 100 with a standard deviation of 15. A researcher thinks that a diet high in raw cornstarch will have a positive or negative effect on blood glucose levels. A sample of 30 patients who have tried the raw cornstarch diet have a mean glucose level of 140. Test the hypothesis that the raw cornstarch had an effect. Show all work

Answer 1

The critical values (z) for 80% CI are obtained from Statkey(images are attached for reference). We perform the z test for the problem and find out the test statistic using the formula mentioned and based on that we make the required conclusion.