Two Means

1. An engineer wanted to know whether the strength of two different concrete mix designs differed significantly. He randomly selected 10 cylinders of each mixture with the following results:

Mixture A: 3960, 4090, 3100, 3830, 3200, 3780, 4080, 2940, 4040, 3700

Mixture B: 4070, 4890, 5020, 4330, 4640, 5220, 4190, 3730, 4120, 4520

Determine whether mixture B is stronger than mixture A at =0.05 level of significance.

1. a. State the null and alternative hypothesis
2. b. Give the p-val
3. c. Give a conclusion for the hypothesis test

2.One Proportion

2. The drug Lipitor is meant to reduce total cholesterol and LDL cholesterol.

In clinical trials, 19 out 0f 863 patients taking 10mg of Lipitor daily complained of flulike symptoms. Suppose that it is known that 1.9% of patients taking competing drugs complain of flulike symptoms. Since this is a larger percentage than patients taking Lipitor.

Is there sufficient evidence to conclude that more than 1.9% of Lipitor users experience flulike symptoms as a side effect at the =0.01 level of significance.

1. a. State the null and alternative hypothesis.
2. b. Give the p-value
3. c. Give a conclusion for the hypothesis test
4. d. Find a 99% confidence Interval
5. e. Write a conclusion for the confidence Internal

3. Consider the following data which is the number of traffic accidents involving children within two kilometers of schools, listed by days of the week.

Day of the week Observed number of accidents

Monday 23

Tuesday 18

Wednesday 17

Thursday 19

Friday 23

Use a Goodness of Fit test to test if accidents are equally likely for all days of the week.

1. a. State the null and alternative hypothesis
2. b. Give the p-value
3. c. Give a conclusion for the hypothesis test.