1. Suppose 14% of people are left handed. What is the probability that a random sample of 200 people will have less than 12% lefties? Be sure to check the conditions to make the necessary assumptions before using the model. Conditions: Randomization: 10% Condition: Success/Failure Condition: Probability:

2. The life of General Electric light bulbs are normally distributed with a mean of 200 hours and a standard deviation 20 hours. a. What is the probability that a randomly selected light bulb will last more that 210 hours? Probability: b. What is the probability that a random sample of 10 light bulbs has a mean life greater than 210 hours? (check assumptions and conditions first) Conditions: Randomization: 10% Condition: Large Enough Sample Condition: Probability:

3. In 2005, the Gallup Poll estimated that 32% of adults believe in ghosts. In a random sample of 200 young adults (ages 18-29), 38% said they believed in ghosts. Is this evidence that young adults are more likely to believe in ghosts?

a. What is the population of interest? Population:

b. Describe p in words. p:

c. Write the Hypotheses. H0: HA:

d. Perform the test using a significance level of 0.10 ( = 0.10) Be sure to show the following: i. Check Assumptions and Conditions ii. Find the P-value. iii. Give the conclusion in context. (3 things needed) i. Conditions: Randomization: 10% Condition: Success/Failure Condition: ii. P-value: iii. Conclusion in context:

e. Explain what the P-value you found means in the context of the problem Explanation:

f. What would be a Type I Error in the context of this problem? Type I Error:

g. What would be a Type II Error in the context of this problem? Type II Error:

h. Check the assumptions and conditions necessary for finding a confidence interval for p. Conditions: Randomization: 10% Condition: Success/Failure Condition:

i. Find a 95% confidence interval for p. Interval:

j. Give your interval in context of the problem. Interval in Context:

k. Interpret what 95% confidence means in this context. Interpretation:

l. What sample size would allow us to increase our confidence level to 99% while reducing the margin of error to only 0.03? Sample size:

4. Insurance companies are interested in knowing the mean weight of cars currently licensed in the United States; they believe it is 3000 pounds. To see if the estimate is correct, they check a random sample of 80 cars. For that group, the mean weight was 2910 pounds with a standard deviation of 532 pounds. Is this strong evidence that the mean weight of all cars is not 3000 pounds?

a. What is the population of interest? Population:

b. Describe in words. :

c. Write the Hypotheses H0: HA:

d. Perform the test using a significance level of 0.05 ( = 0.05) Be sure to show the following: i. Check Assumptions and Conditions ii. Find the P-value. iii. Give the conclusion in context. (3 things needed) i. Conditions: Randomization: 10% Condition: Nearly Normal: ii. P-value: iii. Conclusion in context:

e. Explain what the P-value you found means in the context of the problem Explanation:

f. What would be a Type I Error in the context of this problem? Type I Error:

g. What would be a Type II Error in the context of this problem? Type II Error:

h. Find a 90% confidence interval for . Interval:

i. Give your interval in context of the problem. Interval in Context:

j. Interpret what 90% confidence means in this context. Interpretation:

k. What sample size would allow us to increase our confidence level to 95% while reducing the margin of error to only 50 pounds? Sample size: